diff --git a/Doc/library/email.headerregistry.rst b/Doc/library/email.headerregistry.rst
index 97fcf2a..2e9224a 100644
--- a/Doc/library/email.headerregistry.rst
+++ b/Doc/library/email.headerregistry.rst
@@ -234,11 +234,80 @@
       result in a :exc:`ValueError`.
 
 
-Each of the above classes also has a ``Unique`` variant (for example,
+Many of the above classes also have a ``Unique`` variant (for example,
 ``UniqueUnstructuredHeader``).  The only difference is that in the ``Unique``
 variant, :attr:`~.BaseHeader.max_count` is set to 1.
 
 
+.. class:: MIMEVersionHeader
+
+   There is really only one valid value for the :mailheader:`MIME-Version`
+   header, and that is ``1.0``.  For future proofing, this header class
+   supports other valid version numbers.  If a version number has a valid value
+   per :rfc:`2045`, then the header object will have non-``None`` values for
+   the following attributes:
+
+   .. attribute:: version
+
+      The version number as a string, with any whitespace and/or comments
+      removed.
+
+   .. attribute:: major
+
+      The major version number as an integer
+
+   .. attribute:: minor
+
+      The minor version number as an integer
+
+
+.. class:: ParameterizedMIMEHeader
+
+    MOME headers all start with the prefix 'Content-'.  Each specific header has
+    a certain value, described under the class for that header.  Some can
+    also take a list of supplemental parameters, which have a common format.
+    This class serves as a base for all the MIME headers that take parameters.
+
+    .. attrbibute:: params
+
+       A dictionary mapping parameter names to parameter values.
+
+
+.. class:: ContentTypeHeader
+
+    A :class:`ParameterizedMIMEHheader` class that handles the
+    :mailheader:`Content-Type` header.
+
+    .. attribute:: content_type
+
+       The content type string, in the form ``maintype/subtype``.
+
+    .. attribute:: maintype
+
+    .. attribute:: subtype
+
+
+.. class:: ContentDispositionHeader
+
+    A :class:`ParameterizedMIMEHheader` class that handles the
+    :mailheader:`Content-Disposition` header.
+
+    .. attribute:: content-disposition
+
+       ``inline`` and ``attachment`` are the only valid values in common use.
+
+
+.. class:: ContentTransferEncoding
+
+   Handles the :mailheader:`Content-Transfer-Encoding` header.
+
+   .. attribute:: cte
+
+      Valid values are ``7bit``, ``8bit``, ``base64``, and
+      ``quoted-printable``.  See :rfc:`2045` for more information.
+
+
+
 .. class:: HeaderRegistry(base_class=BaseHeader, \
                           default_class=UnstructuredHeader, \
                           use_default_map=True)
diff --git a/Lib/email/_header_value_parser.py b/Lib/email/_header_value_parser.py
index f4a01f1..1924ed1 100644
--- a/Lib/email/_header_value_parser.py
+++ b/Lib/email/_header_value_parser.py
@@ -68,6 +68,8 @@
 """
 
 import re
+import urllib   # For urllib.parse.unquote
+from collections import namedtuple, OrderedDict
 from email import _encoded_words as _ew
 from email import errors
 from email import utils
@@ -83,6 +85,11 @@
 DOT_ATOM_ENDS = ATOM_ENDS - set('.')
 # '.', '"', and '(' do not end phrases in order to support obs-phrase
 PHRASE_ENDS = SPECIALS - set('."(')
+TSPECIALS = (SPECIALS | set('/?=')) - set('.')
+TOKEN_ENDS = TSPECIALS | WSP
+ASPECIALS = TSPECIALS | set("*'%")
+ATTRIBUTE_ENDS = ASPECIALS | WSP
+EXTENDED_ATTRIBUTE_ENDS = ATTRIBUTE_ENDS - set('%')
 
 def quote_string(value):
     return '"'+str(value).replace('\\', '\\\\').replace('"', r'\"')+'"'
@@ -356,8 +363,12 @@
             self.__class__.__name__,
             self.token_type)
         for token in self:
-            for line in token._pp(indent+'    '):
-                yield line
+            if not hasattr(token, '_pp'):
+                yield (indent + '    !! invalid element in token '
+                                        'list: {!r}'.format(token))
+            else:
+                for line in token._pp(indent+'    '):
+                    yield line
         if self.defects:
             extra = ' Defects: {}'.format(self.defects)
         else:
@@ -567,6 +578,11 @@
     token_type = 'atom'
 
 
+class Token(TokenList):
+
+    token_type = 'token'
+
+
 class EncodedWord(TokenList):
 
     token_type = 'encoded-word'
@@ -602,13 +618,19 @@
                 res.append(x.value)
         return ''.join(res)
 
+    @property
+    def stripped_value(self):
+        for token in self:
+            if token.token_type == 'bare-quoted-string':
+                return token.value
+
 
 class BareQuotedString(QuotedString):
 
     token_type = 'bare-quoted-string'
 
     def __str__(self):
-        return quote_string(''.join(self))
+        return quote_string(''.join(str(x) for x in self))
 
     @property
     def value(self):
@@ -987,6 +1009,180 @@
                 return x.value
 
 
+class MIMEVersion(TokenList):
+
+    token_type = 'mime-version'
+    major = None
+    minor = None
+
+
+class Parameter(TokenList):
+
+    token_type = 'parameter'
+    sectioned = False
+    extended = False
+    charset = 'us-ascii'
+
+    @property
+    def section_number(self):
+        # Because the first token, the attribute (name) eats CFWS, the second
+        # token is always the section if there is one.
+        return self[1].number if self.sectioned else 0
+
+    @property
+    def param_value(self):
+        # This is part of the "handle quoted extended parameters" hack.
+        for token in self:
+            if token.token_type == 'value':
+                return token.stripped_value
+            if token.token_type == 'quoted-string':
+                for token in token:
+                    if token.token_type == 'bare-quoted-string':
+                        for token in token:
+                            if token.token_type == 'value':
+                                return token.stripped_value
+        return ''
+
+
+class InvalidParameter(Parameter):
+
+    token_type = 'invalid-parameter'
+
+
+class Attribute(TokenList):
+
+    token_type = 'attribute'
+
+    @property
+    def stripped_value(self):
+        for token in self:
+            if token.token_type.endswith('attrtext'):
+                return token.value
+
+class Section(TokenList):
+
+    token_type = 'section'
+    number = None
+
+
+class Value(TokenList):
+
+    token_type = 'value'
+
+    @property
+    def stripped_value(self):
+        token = self[0]
+        if token.token_type == 'cfws':
+            token = self[1]
+        if token.token_type.endswith(
+                ('quoted-string', 'attribute', 'extended-attribute')):
+            return token.stripped_value
+        return self.value
+
+
+class MimeParameters(TokenList):
+
+    token_type = 'mime-parameters'
+
+    @property
+    def params(self):
+        # The RFC specifically states that the ordering of parameters is not
+        # guaranteed and may be reordered by the transport layer.  So we have
+        # to assume the RFC 2231 pieces can come in any order.  However, we
+        # output them in the order that we first see a given name, which gives
+        # us a stable __str__.
+        params = OrderedDict()
+        for token in self:
+            if not token.token_type.endswith('parameter'):
+                continue
+            if token[0].token_type != 'attribute':
+                continue
+            name = token[0].value.strip()
+            if name not in params:
+                params[name] = []
+            params[name].append((token.section_number, token))
+        for name, parts in params.items():
+            parts = sorted(parts)
+            # XXX: there might be more recovery we could do here if, for
+            # example, this is really a case of a duplicate attribute name.
+            value_parts = []
+            charset = parts[0][1].charset
+            for i, (section_number, param) in enumerate(parts):
+                if section_number != i:
+                    param.defects.append(errors.InvalidHeaderDefect(
+                        "inconsistent multipart parameter numbering"))
+                value = param.param_value
+                if param.extended:
+                    try:
+                        value = urllib.parse.unquote_to_bytes(value)
+                    except UnicodeEncodeError:
+                        # source had surrogate escaped bytes.  What we do now
+                        # is a bit of an open question.  I'm not sure this is
+                        # the best choice, but it is what the old algorithm did
+                        value = urllib.parse.unquote(value, encoding='latin-1')
+                    else:
+                        try:
+                            value = value.decode(charset, 'surrogateescape')
+                        except LookupError:
+                            # XXX: there should really be a custom defect for
+                            # unknown character set to make it easy to find,
+                            # because otherwise unknown charset is a silent
+                            # failure.
+                            value = value.decode('us-ascii', 'surrogateescape')
+                        if utils._has_surrogates(value):
+                            param.defects.append(errors.UndecodableBytesDefect())
+                value_parts.append(value)
+            value = ''.join(value_parts)
+            yield name, value
+
+    def __str__(self):
+        params = []
+        for name, value in self.params:
+            if value:
+                params.append('{}={}'.format(name, quote_string(value)))
+            else:
+                params.append(name)
+        params = '; '.join(params)
+        return ' ' + params if params else ''
+
+
+class ParameterizedHeaderValue(TokenList):
+
+    @property
+    def params(self):
+        for token in reversed(self):
+            if token.token_type == 'mime-parameters':
+                return token.params
+        return {}
+
+    @property
+    def parts(self):
+        if self and self[-1].token_type == 'mime-parameters':
+            # We don't want to start a new line if all of the params don't fit
+            # after the value, so unwrap the parameter list.
+            return TokenList(self[:-1] + self[-1])
+        return TokenList(self).parts
+
+
+class ContentType(ParameterizedHeaderValue):
+
+    token_type = 'content-type'
+    maintype = 'text'
+    subtype = 'plain'
+
+
+class ContentDisposition(ParameterizedHeaderValue):
+
+    token_type = 'content-disposition'
+    content_disposition = None
+
+
+class ContentTransferEncoding(TokenList):
+
+    token_type = 'content-transfer-encoding'
+    cte = '7bit'
+
+
 class HeaderLabel(TokenList):
 
     token_type = 'header-label'
@@ -1145,6 +1341,13 @@
 _non_atom_end_matcher = re.compile(r"[^{}]+".format(
     ''.join(ATOM_ENDS).replace('\\','\\\\').replace(']','\]'))).match
 _non_printable_finder = re.compile(r"[\x00-\x20\x7F]").findall
+_non_token_end_matcher = re.compile(r"[^{}]+".format(
+    ''.join(TOKEN_ENDS).replace('\\','\\\\').replace(']','\]'))).match
+_non_attribute_end_matcher = re.compile(r"[^{}]+".format(
+    ''.join(ATTRIBUTE_ENDS).replace('\\','\\\\').replace(']','\]'))).match
+_non_extended_attribute_end_matcher = re.compile(r"[^{}]+".format(
+    ''.join(EXTENDED_ATTRIBUTE_ENDS).replace(
+                                    '\\','\\\\').replace(']','\]'))).match
 
 def _validate_xtext(xtext):
     """If input token contains ASCII non-printables, register a defect."""
@@ -2153,3 +2356,598 @@
             address_list.append(ValueTerminal(',', 'list-separator'))
             value = value[1:]
     return address_list, value
+
+#
+# XXX: As I begin to add additional header parsers, I'm realizing we probably
+# have two level of parser routines: the get_XXX methods that get a token in
+# the grammar, and parse_XXX methods that parse an entire field value.  So
+# get_address_list above should really be a parse_ method, as probably should
+# be get_unstructured.
+#
+
+def parse_mime_version(value):
+    """ mime-version = [CFWS] 1*digit [CFWS] "." [CFWS] 1*digit [CFWS]
+
+    """
+    # The [CFWS] is implicit in the RFC 2045 BNF.
+    # XXX: This routine is a bit verbose, should factor out a get_int method.
+    mime_version = MIMEVersion()
+    if not value:
+        mime_version.defects.append(errors.HeaderMissingRequiredValue(
+            "Missing MIME version number (eg: 1.0)"))
+        return mime_version
+    if value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        mime_version.append(token)
+        if not value:
+            mime_version.defects.append(errors.HeaderMissingRequiredValue(
+                "Expected MIME version number but found only CFWS"))
+    digits = ''
+    while value and value[0] != '.' and value[0] not in CFWS_LEADER:
+        digits += value[0]
+        value = value[1:]
+    if not digits.isdigit():
+        mime_version.defects.append(errors.InvalidHeaderDefect(
+            "Expected MIME major version number but found {!r}".format(digits)))
+        mime_version.append(ValueTerminal(digits, 'xtext'))
+    else:
+        mime_version.major = int(digits)
+        mime_version.append(ValueTerminal(digits, 'digits'))
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        mime_version.append(token)
+    if not value or value[0] != '.':
+        if mime_version.major is not None:
+            mime_version.defects.append(errors.InvalidHeaderDefect(
+                "Incomplete MIME version; found only major number"))
+        if value:
+            mime_version.append(ValueTerminal(value, 'xtext'))
+        return mime_version
+    mime_version.append(ValueTerminal('.', 'version-separator'))
+    value = value[1:]
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        mime_version.append(token)
+    if not value:
+        if mime_version.major is not None:
+            mime_version.defects.append(errors.InvalidHeaderDefect(
+                "Incomplete MIME version; found only major number"))
+        return mime_version
+    digits = ''
+    while value and value[0] not in CFWS_LEADER:
+        digits += value[0]
+        value = value[1:]
+    if not digits.isdigit():
+        mime_version.defects.append(errors.InvalidHeaderDefect(
+            "Expected MIME minor version number but found {!r}".format(digits)))
+        mime_version.append(ValueTerminal(digits, 'xtext'))
+    else:
+        mime_version.minor = int(digits)
+        mime_version.append(ValueTerminal(digits, 'digits'))
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        mime_version.append(token)
+    if value:
+        mime_version.defects.append(errors.InvalidHeaderDefect(
+            "Excess non-CFWS text after MIME version"))
+        mime_version.append(ValueTerminal(value, 'xtext'))
+    return mime_version
+
+def get_invalid_parameter(value):
+    """ Read everything up to the next ';'.
+
+    This is outside the formal grammar.  The InvalidParameter TokenList that is
+    returned acts like a Parameter, but the data attributes are None.
+
+    """
+    invalid_parameter = InvalidParameter()
+    while value and value[0] != ';':
+        if value[0] in PHRASE_ENDS:
+            invalid_parameter.append(ValueTerminal(value[0],
+                                                   'misplaced-special'))
+            value = value[1:]
+        else:
+            token, value = get_phrase(value)
+            invalid_parameter.append(token)
+    return invalid_parameter, value
+
+def get_ttext(value):
+    """ttext = <matches _ttext_matcher>
+
+    We allow any non-TOKEN_ENDS in ttext, but add defects to the token's
+    defects list if we find non-ttext characters.  We also register defects for
+    *any* non-printables even though the RFC doesn't exclude all of them,
+    because we follow the spirit of RFC 5322.
+
+    """
+    m = _non_token_end_matcher(value)
+    if not m:
+        raise errors.HeaderParseError(
+            "expected ttext but found '{}'".format(value))
+    ttext = m.group()
+    value = value[len(ttext):]
+    ttext = ValueTerminal(ttext, 'ttext')
+    _validate_xtext(ttext)
+    return ttext, value
+
+def get_token(value):
+    """token = [CFWS] 1*ttext [CFWS]
+
+    The RFC equivalent of ttext is any US-ASCII chars except space, ctls, or
+    tspecials.  We also exclude tabs even though the RFC doesn't.
+
+    The RFC implies the CFWS but is not explicit about it in the BNF.
+
+    """
+    mtoken = Token()
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        mtoken.append(token)
+    if value and value[0] in TOKEN_ENDS:
+        raise errors.HeaderParseError(
+            "expected token but found '{}'".format(value))
+    token, value = get_ttext(value)
+    mtoken.append(token)
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        mtoken.append(token)
+    return mtoken, value
+
+def get_attrtext(value):
+    """attrtext = 1*(any non-ATTRIBUTE_ENDS character)
+
+    We allow any non-ATTRIBUTE_ENDS in attrtext, but add defects to the
+    token's defects list if we find non-attrtext characters.  We also register
+    defects for *any* non-printables even though the RFC doesn't exclude all of
+    them, because we follow the spirit of RFC 5322.
+
+    """
+    m = _non_attribute_end_matcher(value)
+    if not m:
+        raise errors.HeaderParseError(
+            "expected attrtext but found {!r}".format(value))
+    attrtext = m.group()
+    value = value[len(attrtext):]
+    attrtext = ValueTerminal(attrtext, 'attrtext')
+    _validate_xtext(attrtext)
+    return attrtext, value
+
+def get_attribute(value):
+    """ [CFWS] 1*attrtext [CFWS]
+
+    This version of the BNF makes the CFWS explicit, and as usual we use a
+    value terminal for the actual run of characters.  The RFC equivalent of
+    attrtext is the token characters, with the subtraction of '*', "'", and '%'.
+    We include tab in the excluded set just as we do for token.
+
+    """
+    attribute = Attribute()
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        attribute.append(token)
+    if value and value[0] in ATTRIBUTE_ENDS:
+        raise errors.HeaderParseError(
+            "expected token but found '{}'".format(value))
+    token, value = get_attrtext(value)
+    attribute.append(token)
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        attribute.append(token)
+    return attribute, value
+
+def get_extended_attrtext(value):
+    """attrtext = 1*(any non-ATTRIBUTE_ENDS character plus '%')
+
+    This is a special parsing routine so that we get a value that
+    includes % escapes as a single string (which we decode as a single
+    string later).
+
+    """
+    m = _non_extended_attribute_end_matcher(value)
+    if not m:
+        raise errors.HeaderParseError(
+            "expected extended attrtext but found {!r}".format(value))
+    attrtext = m.group()
+    value = value[len(attrtext):]
+    attrtext = ValueTerminal(attrtext, 'extended-attrtext')
+    _validate_xtext(attrtext)
+    return attrtext, value
+
+def get_extended_attribute(value):
+    """ [CFWS] 1*extended_attrtext [CFWS]
+
+    This is like the non-extended version except we allow % characters, so that
+    we can pick up an encoded value as a single string.
+
+    """
+    # XXX: should we have an ExtendedAttribute TokenList?
+    attribute = Attribute()
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        attribute.append(token)
+    if value and value[0] in EXTENDED_ATTRIBUTE_ENDS:
+        raise errors.HeaderParseError(
+            "expected token but found '{}'".format(value))
+    token, value = get_extended_attrtext(value)
+    attribute.append(token)
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        attribute.append(token)
+    return attribute, value
+
+def get_section(value):
+    """ '*' digits
+
+    The formal BNF is more complicated because leading 0s are not allowed.  We
+    check for that and add a defect.  We also assume no CFWS is allowed between
+    the '*' and the digits, though the RFC is not crystal clear on that.
+    The caller should already have dealt with leading CFWS.
+
+    """
+    section = Section()
+    if not value or value[0] != '*':
+        raise errors.HeaderParseError("Expected section but found {}".format(
+                                        value))
+    section.append(ValueTerminal('*', 'section-marker'))
+    value = value[1:]
+    if not value or not value[0].isdigit():
+        raise errors.HeaderParseError("Expected section number but "
+                                      "found {}".format(value))
+    digits = ''
+    while value and value[0].isdigit():
+        digits += value[0]
+        value = value[1:]
+    if digits[0] == '0' and digits != '0':
+        section.defects.append(errors.InvalidHeaderError("section number"
+            "has an invalid leading 0"))
+    section.number = int(digits)
+    section.append(ValueTerminal(digits, 'digits'))
+    return section, value
+
+
+def get_value(value):
+    """ quoted-string / attribute
+
+    """
+    v = Value()
+    if not value:
+        raise errors.HeaderParseError("Expected value but found end of string")
+    leader = None
+    if value[0] in CFWS_LEADER:
+        leader, value = get_cfws(value)
+    if not value:
+        raise errors.HeaderParseError("Expected value but found "
+                                      "only {}".format(leader))
+    if value[0] == '"':
+        token, value = get_quoted_string(value)
+    else:
+        token, value = get_extended_attribute(value)
+    if leader is not None:
+        token[:0] = [leader]
+    v.append(token)
+    return v, value
+
+def get_parameter(value):
+    """ attribute [section] ["*"] [CFWS] "=" value
+
+    The CFWS is implied by the RFC but not made explicit in the BNF.  This
+    simplified form of the BNF from the RFC is made to conform with the RFC BNF
+    through some extra checks.  We do it this way because it makes both error
+    recovery and working with the resulting parse tree easier.
+    """
+    # It is possible CFWS would also be implicitly allowed between the section
+    # and the 'extended-attribute' marker (the '*') , but we've never seen that
+    # in the wild and we will therefore ignore the possibility.
+    param = Parameter()
+    token, value = get_attribute(value)
+    param.append(token)
+    if not value or value[0] == ';':
+        param.defects.append(errors.InvalidHeaderDefect("Parameter contains "
+            "name ({}) but no value".format(token)))
+        return param, value
+    if value[0] == '*':
+        try:
+            token, value = get_section(value)
+            param.sectioned = True
+            param.append(token)
+        except errors.HeaderParseError:
+            pass
+        if not value:
+            raise errors.HeaderParseError("Incomplete parameter")
+        if value[0] == '*':
+            param.append(ValueTerminal('*', 'extended-parameter-marker'))
+            value = value[1:]
+            param.extended = True
+    if value[0] != '=':
+        raise errors.HeaderParseError("Parameter not followed by '='")
+    param.append(ValueTerminal('=', 'parameter-separator'))
+    value = value[1:]
+    leader = None
+    if value and value[0] in CFWS_LEADER:
+        token, value = get_cfws(value)
+        param.append(token)
+    remainder = None
+    appendto = param
+    if param.extended and value and value[0] == '"':
+        # Now for some serious hackery to handle the common invalid case of
+        # double quotes around an extended value.  We also accept (with defect)
+        # a value marked as encoded that isn't really.
+        qstring, remainder = get_quoted_string(value)
+        inner_value = qstring.stripped_value
+        semi_valid = False
+        if param.section_number == 0:
+            if inner_value and inner_value[0] == "'":
+                semi_valid = True
+            else:
+                token, rest = get_attrtext(inner_value)
+                if rest and rest[0] == "'":
+                    semi_valid = True
+        else:
+            try:
+                token, rest = get_extended_attrtext(inner_value)
+            except:
+                pass
+            else:
+                if not rest:
+                    semi_valid = True
+        if semi_valid:
+            param.defects.append(errors.InvalidHeaderDefect(
+                "Quoted string value for extended parameter is invalid"))
+            param.append(qstring)
+            for t in qstring:
+                if t.token_type == 'bare-quoted-string':
+                    t[:] = []
+                    appendto = t
+                    break
+            value = inner_value
+        else:
+            remainder = None
+            param.defects.append(errors.InvalidHeaderDefect(
+                "Parameter marked as extended but appears to have a "
+                "quoted string value that is non-encoded"))
+    if value and value[0] == "'":
+        token = None
+    else:
+        token, value = get_value(value)
+    if not param.extended or param.section_number > 0:
+        if not value or value[0] != "'":
+            appendto.append(token)
+            if remainder is not None:
+                assert not value, value
+                value = remainder
+            return param, value
+        param.defects.append(errors.InvalidHeaderDefect(
+            "Apparent initial-extended-value but attribute "
+            "was not marked as extended or was not initial section"))
+    if not value:
+        # Assume the charset/lang is missing and the token is the value.
+        param.defects.append(errors.InvalidHeaderDefect(
+            "Missing required charset/lang delimiters"))
+        appendto.append(token)
+        if remainder is None:
+            return param, value
+    else:
+        if token is not None:
+            for t in token:
+                if t.token_type == 'extended-attrtext':
+                    break
+            t.token_type == 'attrtext'
+            appendto.append(t)
+            param.charset = t.value
+        if value[0] != "'":
+            raise errors.HeaderParseError("Expected RFC2231 char/lang encoding "
+                                          "delimiter, but found {!r}".format(value))
+        appendto.append(ValueTerminal("'", 'RFC2231 delimiter'))
+        value = value[1:]
+        if value and value[0] != "'":
+            token, value = get_attrtext(value)
+            appendto.append(token)
+            param.lang = token.value
+            if not value or value[0] != "'":
+                raise errors.HeaderParseError("Expected RFC2231 char/lang encoding "
+                                  "delimiter, but found {}".format(value))
+        appendto.append(ValueTerminal("'", 'RFC2231 delimiter'))
+        value = value[1:]
+    if remainder is not None:
+        # Treat the rest of value as bare quoted string content.
+        v = Value()
+        while value:
+            if value[0] in WSP:
+                token, value = get_fws(value)
+            else:
+                token, value = get_qcontent(value)
+            v.append(token)
+        token = v
+    else:
+        token, value = get_value(value)
+    appendto.append(token)
+    if remainder is not None:
+        assert not value, value
+        value = remainder
+    return param, value
+
+def parse_mime_parameters(value):
+    """ parameter *( ";" parameter )
+
+    That BNF is meant to indicate this routine should only be called after
+    finding and handling the leading ';'.  There is no corresponding rule in
+    the formal RFC grammar, but it is more convenient for us for the set of
+    parameters to be treated as its own TokenList.
+
+    This is 'parse' routine because it consumes the reminaing value, but it
+    would never be called to parse a full header.  Instead it is called to
+    parse everything after the non-parameter value of a specific MIME header.
+
+    """
+    mime_parameters = MimeParameters()
+    while value:
+        try:
+            token, value = get_parameter(value)
+            mime_parameters.append(token)
+        except errors.HeaderParseError as err:
+            leader = None
+            if value[0] in CFWS_LEADER:
+                leader, value = get_cfws(value)
+            if not value:
+                mime_parameters.append(leader)
+                return mime_parameters
+            if value[0] == ';':
+                if leader is not None:
+                    mime_parameters.append(leader)
+                mime_parameters.defects.append(errors.InvalidHeaderDefect(
+                    "parameter entry with no content"))
+            else:
+                token, value = get_invalid_parameter(value)
+                if leader:
+                    token[:0] = [leader]
+                mime_parameters.append(token)
+                mime_parameters.defects.append(errors.InvalidHeaderDefect(
+                    "invalid parameter {!r}".format(token)))
+        if value and value[0] != ';':
+            # Junk after the otherwise valid parameter.  Mark it as
+            # invalid, but it will have a value.
+            param = mime_parameters[-1]
+            param.token_type = 'invalid-parameter'
+            token, value = get_invalid_parameter(value)
+            param.extend(token)
+            mime_parameters.defects.append(errors.InvalidHeaderDefect(
+                "parameter with invalid trailing text {!r}".format(token)))
+        if value:
+            # Must be a ';' at this point.
+            mime_parameters.append(ValueTerminal(';', 'parameter-separator'))
+            value = value[1:]
+    return mime_parameters
+
+def _find_mime_parameters(tokenlist, value):
+    """Do our best to find the parameters in an invalid MIME header
+
+    """
+    while value and value[0] != ';':
+        if value[0] in PHRASE_ENDS:
+            tokenlist.append(ValueTerminal(value[0], 'misplaced-special'))
+            value = value[1:]
+        else:
+            token, value = get_phrase(value)
+            tokenlist.append(token)
+    if not value:
+        return
+    tokenlist.append(ValueTerminal(';', 'parameter-separator'))
+    tokenlist.append(parse_mime_parameters(value[1:]))
+
+def parse_content_type_header(value):
+    """ maintype "/" subtype *( ";" parameter )
+
+    The maintype and substype are tokens.  Theoretically they could
+    be checked against the official IANA list + x-token, but we
+    don't do that.
+    """
+    ctype = ContentType()
+    recover = False
+    if not value:
+        ctype.defects.append(errors.HeaderMissingRequiredValue(
+            "Missing content type specification"))
+        return ctype
+    try:
+        token, value = get_token(value)
+    except errors.HeaderParseError:
+        ctype.defects.append(errors.InvalidHeaderDefect(
+            "Expected content maintype but found {!r}".format(value)))
+        _find_mime_parameters(ctype, value)
+        return ctype
+    ctype.append(token)
+    # XXX: If we really want to follow the formal grammer we should make
+    # mantype and subtype specialized TokenLists here.  Probably not worth it.
+    if not value or value[0] != '/':
+        ctype.defects.append(errors.InvalidHeaderDefect(
+            "Invalid content type"))
+        if value:
+            _find_mime_parameters(ctype, value)
+        return ctype
+    ctype.maintype = token.value.strip().lower()
+    ctype.append(ValueTerminal('/', 'content-type-separator'))
+    value = value[1:]
+    try:
+        token, value = get_token(value)
+    except errors.HeaderParseError:
+        ctype.defects.append(errors.InvalidHeaderDefect(
+            "Expected content subtype but found {!r}".format(value)))
+        _find_mime_parameters(ctype, value)
+        return ctype
+    ctype.append(token)
+    ctype.subtype = token.value.strip().lower()
+    if not value:
+        return ctype
+    if value[0] != ';':
+        ctype.defects.append(errors.InvalidHeaderDefect(
+            "Only parameters are valid after content type, but "
+            "found {!r}".format(value)))
+        # The RFC requires that a syntactically invalid content-type be treated
+        # as text/plain.  Perhaps we should postel this, but we should probably
+        # only do that if we were checking the subtype value against IANA.
+        del ctype.maintype, ctype.subtype
+        _find_mime_parameters(ctype, value)
+        return ctype
+    ctype.append(ValueTerminal(';', 'parameter-separator'))
+    ctype.append(parse_mime_parameters(value[1:]))
+    return ctype
+
+def parse_content_disposition_header(value):
+    """ disposition-type *( ";" parameter )
+
+    """
+    disp_header = ContentDisposition()
+    if not value:
+        disp_header.defects.append(errors.HeaderMissingRequiredValue(
+            "Missing content disposition"))
+        return disp_header
+    try:
+        token, value = get_token(value)
+    except errors.HeaderParseError:
+        ctype.defects.append(errors.InvalidHeaderDefect(
+            "Expected content disposition but found {!r}".format(value)))
+        _find_mime_parameters(disp_header, value)
+        return disp_header
+    disp_header.append(token)
+    disp_header.content_disposition = token.value.strip().lower()
+    if not value:
+        return disp_header
+    if value[0] != ';':
+        disp_header.defects.append(errors.InvalidHeaderDefect(
+            "Only parameters are valid after content disposition, but "
+            "found {!r}".format(value)))
+        _find_mime_parameters(disp_header, value)
+        return disp_header
+    disp_header.append(ValueTerminal(';', 'parameter-separator'))
+    disp_header.append(parse_mime_parameters(value[1:]))
+    return disp_header
+
+def parse_content_transfer_encoding_header(value):
+    """ mechanism
+
+    """
+    # We should probably validate the values, since the list is fixed.
+    cte_header = ContentTransferEncoding()
+    if not value:
+        cte_header.defects.append(errors.HeaderMissingRequiredValue(
+            "Missing content transfer encoding"))
+        return cte_header
+    try:
+        token, value = get_token(value)
+    except errors.HeaderParseError:
+        ctype.defects.append(errors.InvalidHeaderDefect(
+            "Expected content trnasfer encoding but found {!r}".format(value)))
+    else:
+        cte_header.append(token)
+        cte_header.cte = token.value.strip().lower()
+    if not value:
+        return cte_header
+    while value:
+        cte_header.defects.append(errors.InvalidHeaderDefect(
+            "Extra text after content transfer encoding"))
+        if value[0] in PHRASE_ENDS:
+            cte_header.append(ValueTerminal(value[0], 'misplaced-special'))
+            value = value[1:]
+        else:
+            token, value = get_phrase(value)
+            cte_header.append(token)
+    return cte_header
diff --git a/Lib/email/headerregistry.py b/Lib/email/headerregistry.py
index 6588546..1fae950 100644
--- a/Lib/email/headerregistry.py
+++ b/Lib/email/headerregistry.py
@@ -391,24 +391,151 @@
     max_count = 1
 
 
+class MIMEVersionHeader:
+
+    max_count = 1
+
+    value_parser = staticmethod(parser.parse_mime_version)
+
+    @classmethod
+    def parse(cls, value, kwds):
+        kwds['parse_tree'] = parse_tree = cls.value_parser(value)
+        kwds['decoded'] = str(parse_tree)
+        kwds['defects'].extend(parse_tree.all_defects)
+        kwds['major'] = None if parse_tree.minor is None else parse_tree.major
+        kwds['minor'] = parse_tree.minor
+        if parse_tree.minor is not None:
+            kwds['version'] = '{}.{}'.format(kwds['major'], kwds['minor'])
+        else:
+            kwds['version'] = None
+
+    def init(self, *args, **kw):
+        self._version = kw.pop('version')
+        self._major = kw.pop('major')
+        self._minor = kw.pop('minor')
+        super().init(*args, **kw)
+
+    @property
+    def major(self):
+        return self._major
+
+    @property
+    def minor(self):
+        return self._minor
+
+    @property
+    def version(self):
+        return self._version
+
+
+class ParameterizedMIMEHeader:
+
+    # Mixin that handles the params dict.  Must be subclassed and
+    # a property value_parser for the specific header provided.
+
+    max_count = 1
+
+    @classmethod
+    def parse(cls, value, kwds):
+        kwds['parse_tree'] = parse_tree = cls.value_parser(value)
+        kwds['decoded'] = str(parse_tree)
+        kwds['defects'].extend(parse_tree.all_defects)
+        if parse_tree.params is None:
+            kwds['params'] = {}
+        else:
+            # The MIME RFCs specify that parameter ordering is arbitrary.
+            kwds['params'] = {utils._sanitize(name).lower():
+                                    utils._sanitize(value)
+                               for name, value in parse_tree.params}
+
+    def init(self, *args, **kw):
+        self._params = kw.pop('params')
+        super().init(*args, **kw)
+
+    @property
+    def params(self):
+        return self._params.copy()
+
+
+class ContentTypeHeader(ParameterizedMIMEHeader):
+
+    value_parser = staticmethod(parser.parse_content_type_header)
+
+    def init(self, *args, **kw):
+        super().init(*args, **kw)
+        self._maintype = utils._sanitize(self._parse_tree.maintype)
+        self._subtype = utils._sanitize(self._parse_tree.subtype)
+
+    @property
+    def maintype(self):
+        return self._maintype
+
+    @property
+    def subtype(self):
+        return self._subtype
+
+    @property
+    def content_type(self):
+        return self.maintype + '/' + self.subtype
+
+
+class ContentDispositionHeader(ParameterizedMIMEHeader):
+
+    value_parser = staticmethod(parser.parse_content_disposition_header)
+
+    def init(self, *args, **kw):
+        super().init(*args, **kw)
+        cd = self._parse_tree.content_disposition
+        self._content_disposition = cd if cd is None else utils._sanitize(cd)
+
+    @property
+    def content_disposition(self):
+        return self._content_disposition
+
+
+class ContentTransferEncodingHeader:
+
+    max_count = 1
+
+    value_parser = staticmethod(parser.parse_content_transfer_encoding_header)
+
+    @classmethod
+    def parse(cls, value, kwds):
+        kwds['parse_tree'] = parse_tree = cls.value_parser(value)
+        kwds['decoded'] = str(parse_tree)
+        kwds['defects'].extend(parse_tree.all_defects)
+
+    def init(self, *args, **kw):
+        super().init(*args, **kw)
+        self._cte = utils._sanitize(self._parse_tree.cte)
+
+    @property
+    def cte(self):
+        return self._cte
+
+
 # The header factory #
 
 _default_header_map = {
-    'subject':          UniqueUnstructuredHeader,
-    'date':             UniqueDateHeader,
-    'resent-date':      DateHeader,
-    'orig-date':        UniqueDateHeader,
-    'sender':           UniqueSingleAddressHeader,
-    'resent-sender':    SingleAddressHeader,
-    'to':               UniqueAddressHeader,
-    'resent-to':        AddressHeader,
-    'cc':               UniqueAddressHeader,
-    'resent-cc':        AddressHeader,
-    'bcc':              UniqueAddressHeader,
-    'resent-bcc':       AddressHeader,
-    'from':             UniqueAddressHeader,
-    'resent-from':      AddressHeader,
-    'reply-to':         UniqueAddressHeader,
+    'subject':                      UniqueUnstructuredHeader,
+    'date':                         UniqueDateHeader,
+    'resent-date':                  DateHeader,
+    'orig-date':                    UniqueDateHeader,
+    'sender':                       UniqueSingleAddressHeader,
+    'resent-sender':                SingleAddressHeader,
+    'to':                           UniqueAddressHeader,
+    'resent-to':                    AddressHeader,
+    'cc':                           UniqueAddressHeader,
+    'resent-cc':                    AddressHeader,
+    'bcc':                          UniqueAddressHeader,
+    'resent-bcc':                   AddressHeader,
+    'from':                         UniqueAddressHeader,
+    'resent-from':                  AddressHeader,
+    'reply-to':                     UniqueAddressHeader,
+    'mime-version':                 MIMEVersionHeader,
+    'content-type':                 ContentTypeHeader,
+    'content-disposition':          ContentDispositionHeader,
+    'content-transfer-encoding':    ContentTransferEncodingHeader,
     }
 
 class HeaderRegistry:
diff --git a/Lib/test/test_email/test__header_value_parser.py b/Lib/test/test_email/test__header_value_parser.py
index 2161af1..6101e19 100644
--- a/Lib/test/test_email/test__header_value_parser.py
+++ b/Lib/test/test_email/test__header_value_parser.py
@@ -3,7 +3,7 @@
 from email import _header_value_parser as parser
 from email import errors
 from email import policy
-from test.test_email import TestEmailBase
+from test.test_email import TestEmailBase, parameterize
 
 class TestTokens(TestEmailBase):
 
@@ -28,7 +28,32 @@
         self.assertDefectsEqual(parts[2].all_defects, [errors.UndecodableBytesDefect])
 
 
-class TestParser(TestEmailBase):
+class TestParserMixin:
+
+    def _assert_results(self, tl, rest, string, value, defects, remainder,
+                        comments=None):
+        self.assertEqual(str(tl), string)
+        self.assertEqual(tl.value, value)
+        self.assertDefectsEqual(tl.all_defects, defects)
+        self.assertEqual(rest, remainder)
+        if comments is not None:
+            self.assertEqual(tl.comments, comments)
+
+    def _test_get_x(self, method, source, string, value, defects,
+                          remainder, comments=None):
+        tl, rest = method(source)
+        self._assert_results(tl, rest, string, value, defects, remainder,
+                             comments=None)
+        return tl
+
+    def _test_parse_x(self, method, input, string, value, defects,
+                             comments=None):
+        tl = method(input)
+        self._assert_results(tl, '', string, value, defects, '', comments)
+        return tl
+
+
+class TestParser(TestParserMixin, TestEmailBase):
 
     # _wsp_splitter
 
@@ -49,19 +74,6 @@
                                               ['foo', ' \t ', 'def jik'])
 
 
-    # test harness
-
-    def _test_get_x(self, method, input, string, value, defects,
-                          remainder, comments=None):
-        token, rest = method(input)
-        self.assertEqual(str(token), string)
-        self.assertEqual(token.value, value)
-        self.assertDefectsEqual(token.all_defects, defects)
-        self.assertEqual(rest, remainder)
-        if comments is not None:
-            self.assertEqual(token.comments, comments)
-        return token
-
     # get_fws
 
     def test_get_fws_only(self):
@@ -2390,6 +2402,67 @@
                          str(address_list.mailboxes[2]))
 
 
+@parameterize
+class Test_parse_mime_version(TestParserMixin, TestEmailBase):
+
+    def mime_version_as_value(self,
+                              value,
+                              tl_str,
+                              tl_value,
+                              major,
+                              minor,
+                              defects):
+        mime_version = self._test_parse_x(parser.parse_mime_version,
+            value, tl_str, tl_value, defects)
+        self.assertEqual(mime_version.major, major)
+        self.assertEqual(mime_version.minor, minor)
+
+    mime_version_params = {
+
+        'rfc_2045_1': (
+            '1.0',
+            '1.0',
+            '1.0',
+            1,
+            0,
+            []),
+
+        'RFC_2045_2': (
+            '1.0 (produced by MetaSend Vx.x)',
+            '1.0 (produced by MetaSend Vx.x)',
+            '1.0 ',
+            1,
+            0,
+            []),
+
+        'RFC_2045_3': (
+            '(produced by MetaSend Vx.x) 1.0',
+            '(produced by MetaSend Vx.x) 1.0',
+            ' 1.0',
+            1,
+            0,
+            []),
+
+        'RFC_2045_4': (
+            '1.(produced by MetaSend Vx.x)0',
+            '1.(produced by MetaSend Vx.x)0',
+            '1. 0',
+            1,
+            0,
+            []),
+
+        'empty': (
+            '',
+            '',
+            '',
+            None,
+            None,
+            [errors.HeaderMissingRequiredValue]),
+
+        }
+
+
+
 class TestFolding(TestEmailBase):
 
     policy = policy.default
diff --git a/Lib/test/test_email/test_email.py b/Lib/test/test_email/test_email.py
index 8cc2da0..003df96 100644
--- a/Lib/test/test_email/test_email.py
+++ b/Lib/test/test_email/test_email.py
@@ -259,6 +259,7 @@
         self.assertTrue(lines[0].startswith('From '))
         eq(text, NL.join(lines[1:]))
 
+    # test_headerregistry.TestContentTypeHeader.bad_params
     def test_bad_param(self):
         msg = email.message_from_string("Content-Type: blarg; baz; boo\n")
         self.assertEqual(msg.get_param('baz'), '')
@@ -292,6 +293,7 @@
         eq(msg.get_params(header='x-header'),
            [('foo', ''), ('bar', 'one'), ('baz', 'two')])
 
+    # test_headerregistry.TestContentTypeHeader.spaces_around_param_equals
     def test_get_param_liberal(self):
         msg = Message()
         msg['Content-Type'] = 'Content-Type: Multipart/mixed; boundary = "CPIMSSMTPC06p5f3tG"'
@@ -314,10 +316,12 @@
         # msg.get_param("weird")
         # yet.
 
+    # test_headerregistry.TestContentTypeHeader.spaces_around_semis
     def test_get_param_funky_continuation_lines(self):
         msg = self._msgobj('msg_22.txt')
         self.assertEqual(msg.get_payload(1).get_param('name'), 'wibble.JPG')
 
+    # test_headerregistry.TestContentTypeHeader.semis_inside_quotes
     def test_get_param_with_semis_in_quotes(self):
         msg = email.message_from_string(
             'Content-Type: image/pjpeg; name="Jim&amp;&amp;Jill"\n')
@@ -325,6 +329,7 @@
         self.assertEqual(msg.get_param('name', unquote=False),
                          '"Jim&amp;&amp;Jill"')
 
+    # test_headerregistry.TestContentTypeHeader.quotes_inside_rfc2231_value
     def test_get_param_with_quotes(self):
         msg = email.message_from_string(
             'Content-Type: foo; bar*0="baz\\"foobar"; bar*1="\\"baz"')
@@ -1885,6 +1890,7 @@
                     "\nContent-Transfer-Encoding: {}".format(cte)))
             self.assertEqual(len(msg.defects), 0)
 
+    # test_headerregistry.TestContentTyopeHeader invalid_1 and invalid_2.
     def test_invalid_content_type(self):
         eq = self.assertEqual
         neq = self.ndiffAssertEqual
@@ -3437,6 +3443,7 @@
         self.assertEqual(msg.get_content_maintype(), "text")
         self.assertEqual(msg.get_content_subtype(), "pl\uFFFDin")
 
+    # test_headerregistry.TestContentTypeHeader.non_ascii_in_params
     def test_get_params_with_8bit(self):
         msg = email.message_from_bytes(
             'X-Header: foo=\xa7ne; b\xa7r=two; baz=three\n'.encode('latin-1'))
@@ -3446,6 +3453,7 @@
         # XXX: someday you might be able to get 'b\xa7r', for now you can't.
         self.assertEqual(msg.get_param('b\xa7r', header='x-header'), None)
 
+    # test_headerregistry.TestContentTypeHeader.non_ascii_in_rfc2231_value
     def test_get_rfc2231_params_with_8bit(self):
         msg = email.message_from_bytes(textwrap.dedent("""\
             Content-Type: text/plain; charset=us-ascii;
@@ -4491,6 +4499,9 @@
 
 # Test RFC 2231 header parameters (en/de)coding
 class TestRFC2231(TestEmailBase):
+
+    # test_headerregistry.TestContentTypeHeader.rfc2231_encoded_with_double_quotes
+    # test_headerregistry.TestContentTypeHeader.rfc2231_single_quote_inside_double_quotes
     def test_get_param(self):
         eq = self.assertEqual
         msg = self._msgobj('msg_29.txt')
@@ -4576,11 +4587,15 @@
 -Me
 """)
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_encoded_charset
+    # I changed the charset name, though, because the one in the file isn't
+    # a legal charset name.  Should add a test for an illegal charset.
     def test_rfc2231_get_content_charset(self):
         eq = self.assertEqual
         msg = self._msgobj('msg_32.txt')
         eq(msg.get_content_charset(), 'us-ascii')
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_encoded_no_double_quotes
     def test_rfc2231_parse_rfc_quoting(self):
         m = textwrap.dedent('''\
             Content-Disposition: inline;
@@ -4594,6 +4609,7 @@
                          'This is even more ***fun*** is it not.pdf')
         self.assertEqual(m, msg.as_string())
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_encoded_with_double_quotes
     def test_rfc2231_parse_extra_quoting(self):
         m = textwrap.dedent('''\
             Content-Disposition: inline;
@@ -4607,6 +4623,9 @@
                          'This is even more ***fun*** is it not.pdf')
         self.assertEqual(m, msg.as_string())
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_no_language_or_charset
+    # but new test uses *0* because otherwise lang/charset is not valid.
+    # test_headerregistry.TestContentTypeHeader.rfc2231_segmented_normal_values
     def test_rfc2231_no_language_or_charset(self):
         m = '''\
 Content-Transfer-Encoding: 8bit
@@ -4621,6 +4640,7 @@
             param,
             'file____C__DOCUMENTS_20AND_20SETTINGS_FABIEN_LOCAL_20SETTINGS_TEMP_nsmail.htm')
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_encoded_no_charset
     def test_rfc2231_no_language_or_charset_in_filename(self):
         m = '''\
 Content-Disposition: inline;
@@ -4633,6 +4653,7 @@
         self.assertEqual(msg.get_filename(),
                          'This is even more ***fun*** is it not.pdf')
 
+    # Duplicate of previous test?
     def test_rfc2231_no_language_or_charset_in_filename_encoded(self):
         m = '''\
 Content-Disposition: inline;
@@ -4645,6 +4666,8 @@
         self.assertEqual(msg.get_filename(),
                          'This is even more ***fun*** is it not.pdf')
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_partly_encoded,
+    # but the test below is wrong (the first part should be decoded).
     def test_rfc2231_partly_encoded(self):
         m = '''\
 Content-Disposition: inline;
@@ -4696,6 +4719,7 @@
         self.assertEqual(msg.get_content_charset(),
                          'this is even more ***fun*** is it not.pdf')
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_unknown_charset_treated_as_ascii
     def test_rfc2231_bad_encoding_in_filename(self):
         m = '''\
 Content-Disposition: inline;
@@ -4762,6 +4786,7 @@
         eq(language, None)
         eq(s, "Frank's Document")
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_single_quote_inside_double_quotes
     def test_rfc2231_single_tick_in_filename(self):
         m = """\
 Content-Type: application/x-foo; name*0=\"Frank's\"; name*1=\" Document\"
@@ -4772,6 +4797,7 @@
         self.assertFalse(isinstance(param, tuple))
         self.assertEqual(param, "Frank's Document")
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_single_quote_in_value_with_charset_and_lang
     def test_rfc2231_tick_attack_extended(self):
         eq = self.assertEqual
         m = """\
@@ -4785,6 +4811,7 @@
         eq(language, 'en-us')
         eq(s, "Frank's Document")
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_single_quote_in_non_encoded_value
     def test_rfc2231_tick_attack(self):
         m = """\
 Content-Type: application/x-foo;
@@ -4796,6 +4823,7 @@
         self.assertFalse(isinstance(param, tuple))
         self.assertEqual(param, "us-ascii'en-us'Frank's Document")
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_single_quotes_inside_quotes
     def test_rfc2231_no_extended_values(self):
         eq = self.assertEqual
         m = """\
@@ -4805,6 +4833,7 @@
         msg = email.message_from_string(m)
         eq(msg.get_param('name'), "Frank's Document")
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_encoded_then_unencoded_segments
     def test_rfc2231_encoded_then_unencoded_segments(self):
         eq = self.assertEqual
         m = """\
@@ -4820,6 +4849,8 @@
         eq(language, 'en-us')
         eq(s, 'My Document For You')
 
+    # test_headerregistry.TestContentTypeHeader.rfc2231_unencoded_then_encoded_segments
+    # test_headerregistry.TestContentTypeHeader.rfc2231_quoted_unencoded_then_encoded_segments
     def test_rfc2231_unencoded_then_encoded_segments(self):
         eq = self.assertEqual
         m = """\
diff --git a/Lib/test/test_email/test_headerregistry.py b/Lib/test/test_email/test_headerregistry.py
index fc11fba..eba81f2 100644
--- a/Lib/test/test_email/test_headerregistry.py
+++ b/Lib/test/test_email/test_headerregistry.py
@@ -9,6 +9,9 @@
 from email.headerregistry import Address, Group
 
 
+DITTO = object()
+
+
 class TestHeaderRegistry(TestEmailBase):
 
     def test_arbitrary_name_unstructured(self):
@@ -176,6 +179,789 @@
 
 
 @parameterize
+class TestContentTypeHeader(TestHeaderBase):
+
+    def content_type_as_value(self,
+                              source,
+                              content_type,
+                              maintype,
+                              subtype,
+                              *args):
+        l = len(args)
+        parmdict = args[0] if l>0 else {}
+        defects =  args[1] if l>1 else []
+        decoded =  args[2] if l>2 and args[2] is not DITTO else source
+        header = 'Content-Type:' + ' ' if source else ''
+        folded = args[3] if l>3 else header + source + '\n'
+        h = self.make_header('Content-Type', source)
+        self.assertEqual(h.content_type, content_type)
+        self.assertEqual(h.maintype, maintype)
+        self.assertEqual(h.subtype, subtype)
+        self.assertEqual(h.params, parmdict)
+        self.assertDefectsEqual(h.defects, defects)
+        self.assertEqual(h, decoded)
+        self.assertEqual(h.fold(policy=policy.default), folded)
+
+    content_type_params = {
+
+        # Examples from RFC 2045.
+
+        'RFC_2045_1': (
+            'text/plain; charset=us-ascii (Plain text)',
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'us-ascii'},
+            [],
+            'text/plain; charset="us-ascii"'),
+
+        'RFC_2045_2': (
+            'text/plain; charset=us-ascii',
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'us-ascii'},
+            [],
+            'text/plain; charset="us-ascii"'),
+
+        'RFC_2045_3': (
+            'text/plain; charset="us-ascii"',
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'us-ascii'}),
+
+        # RFC 2045 5.2 says syntactically invalid values are to be treated as
+        # text/plain.
+
+        'no_subtype_in_content_type': (
+            'text/',
+            'text/plain',
+            'text',
+            'plain',
+            {},
+            [errors.InvalidHeaderDefect]),
+
+        'no_slash_in_content_type': (
+            'foo',
+            'text/plain',
+            'text',
+            'plain',
+            {},
+            [errors.InvalidHeaderDefect]),
+
+        'junk_text_in_content_type': (
+            '<crazy "stuff">',
+            'text/plain',
+            'text',
+            'plain',
+            {},
+            [errors.InvalidHeaderDefect]),
+
+        'too_many_slashes_in_content_type': (
+            'image/jpeg/foo',
+            'text/plain',
+            'text',
+            'plain',
+            {},
+            [errors.InvalidHeaderDefect]),
+
+        # But unknown names are OK.  We could make non-IANA names a defect, but
+        # by not doing so we make ourselves future proof.  The fact that they
+        # are unknown will be detectable by the fact that they don't appear in
+        # the mime_registry...and the application is free to extend that list
+        # to handle them even if the core library doesn't.
+
+        'unknown_content_type': (
+            'bad/names',
+            'bad/names',
+            'bad',
+            'names'),
+
+        # The content type is case insensitive, and CFWS is ignored.
+
+        'mixed_case_content_type': (
+            'ImAge/JPeg',
+            'image/jpeg',
+            'image',
+            'jpeg'),
+
+        'spaces_in_content_type': (
+            '  text  /  plain  ',
+            'text/plain',
+            'text',
+            'plain'),
+
+        'cfws_in_content_type': (
+            '(foo) text (bar)/(baz)plain(stuff)',
+            'text/plain',
+            'text',
+            'plain'),
+
+        # test some parameters (more tests could be added for parameters
+        # associated with other content types, but since parameter parsing is
+        # generic they would be redundant for the current implementation).
+
+        'charset_param': (
+            'text/plain; charset="utf-8"',
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'utf-8'}),
+
+        'capitalized_charset': (
+            'text/plain; charset="US-ASCII"',
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'US-ASCII'}),
+
+        'unknown_charset': (
+            'text/plain; charset="fOo"',
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'fOo'}),
+
+        'capitalized_charset_param_name_and_comment': (
+            'text/plain; (interjection) Charset="utf-8"',
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'utf-8'},
+            [],
+            # Should the parameter name be lowercased here?
+            'text/plain; Charset="utf-8"'),
+
+        # Since this is pretty much the ur-mimeheader, we'll put all the tests
+        # that exercise the parameter parsing and formatting here.
+        #
+        # XXX: question: is minimal quoting preferred?
+
+        'unquoted_param_value': (
+            'text/plain; title=foo',
+            'text/plain',
+            'text',
+            'plain',
+            {'title': 'foo'},
+            [],
+            'text/plain; title="foo"'),
+
+        'param_value_with_tspecials': (
+            'text/plain; title="(bar)foo blue"',
+            'text/plain',
+            'text',
+            'plain',
+            {'title': '(bar)foo blue'}),
+
+        'param_with_extra_quoted_whitespace': (
+            'text/plain; title="  a     loong  way \t home   "',
+            'text/plain',
+            'text',
+            'plain',
+            {'title': '  a     loong  way \t home   '}),
+
+        'bad_params': (
+            'blarg; baz; boo',
+            'text/plain',
+            'text',
+            'plain',
+            {'baz': '', 'boo': ''},
+            [errors.InvalidHeaderDefect]*3),
+
+        'spaces_around_param_equals': (
+            'Multipart/mixed; boundary = "CPIMSSMTPC06p5f3tG"',
+            'multipart/mixed',
+            'multipart',
+            'mixed',
+            {'boundary': 'CPIMSSMTPC06p5f3tG'},
+            [],
+            'Multipart/mixed; boundary="CPIMSSMTPC06p5f3tG"'),
+
+        'spaces_around_semis': (
+            ('image/jpeg; name="wibble.JPG" ; x-mac-type="4A504547" ; '
+                'x-mac-creator="474B4F4E"'),
+            'image/jpeg',
+            'image',
+            'jpeg',
+            {'name': 'wibble.JPG',
+             'x-mac-type': '4A504547',
+             'x-mac-creator': '474B4F4E'},
+            [],
+            ('image/jpeg; name="wibble.JPG"; x-mac-type="4A504547"; '
+                'x-mac-creator="474B4F4E"'),
+            # XXX: it could be that we will eventually prefer to fold starting
+            # from the decoded value, in which case these spaces and similar
+            # spaces in other tests will be wrong.
+            ('Content-Type: image/jpeg; name="wibble.JPG" ; '
+                'x-mac-type="4A504547" ;\n'
+             ' x-mac-creator="474B4F4E"\n'),
+            ),
+
+        'semis_inside_quotes': (
+            'image/jpeg; name="Jim&amp;&amp;Jill"',
+            'image/jpeg',
+            'image',
+            'jpeg',
+            {'name': 'Jim&amp;&amp;Jill'}),
+
+        'single_quotes_inside_quotes': (
+            'image/jpeg; name="Jim \'Bob\' Jill"',
+            'image/jpeg',
+            'image',
+            'jpeg',
+            {'name': "Jim 'Bob' Jill"}),
+
+        'double_quotes_inside_quotes': (
+            r'image/jpeg; name="Jim \"Bob\" Jill"',
+            'image/jpeg',
+            'image',
+            'jpeg',
+            {'name': 'Jim "Bob" Jill'},
+            [],
+            r'image/jpeg; name="Jim \"Bob\" Jill"'),
+
+        # XXX: This test works except for the refolding of the header.  I'll
+        # deal with that bug when I deal with the other folding bugs.
+        #'non_ascii_in_params': (
+        #    ('foo\xa7/bar; b\xa7r=two; '
+        #        'baz=thr\xa7e'.encode('latin-1').decode('us-ascii',
+        #                                                'surrogateescape')),
+        #    'foo\uFFFD/bar',
+        #    'foo\uFFFD',
+        #    'bar',
+        #    {'b\uFFFDr': 'two', 'baz': 'thr\uFFFDe'},
+        #    [errors.UndecodableBytesDefect]*3,
+        #    'foo�/bar; b�r="two"; baz="thr�e"',
+        #    ),
+
+        # RFC 2231 parameter tests.
+
+        'rfc2231_segmented_normal_values': (
+            'image/jpeg; name*0="abc"; name*1=".html"',
+            'image/jpeg',
+            'image',
+            'jpeg',
+            {'name': "abc.html"},
+            [],
+            'image/jpeg; name="abc.html"'),
+
+        'quotes_inside_rfc2231_value': (
+            r'image/jpeg; bar*0="baz\"foobar"; bar*1="\"baz"',
+            'image/jpeg',
+            'image',
+            'jpeg',
+            {'bar': 'baz"foobar"baz'},
+            [],
+            r'image/jpeg; bar="baz\"foobar\"baz"'),
+
+        # XXX: This test works except for the refolding of the header.  I'll
+        # deal with that bug when I deal with the other folding bugs.
+        #'non_ascii_rfc2231_value': (
+        #    ('text/plain; charset=us-ascii; '
+        #     "title*=us-ascii'en'This%20is%20"
+        #     'not%20f\xa7n').encode('latin-1').decode('us-ascii',
+        #                                             'surrogateescape'),
+        #    'text/plain',
+        #    'text',
+        #    'plain',
+        #    {'charset': 'us-ascii', 'title': 'This is not f\uFFFDn'},
+        #     [errors.UndecodableBytesDefect],
+        #     'text/plain; charset="us-ascii"; title="This is not f�n"'),
+
+        'rfc2231_encoded_charset': (
+            'text/plain; charset*=ansi-x3.4-1968\'\'us-ascii',
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'us-ascii'},
+            [],
+            'text/plain; charset="us-ascii"'),
+
+        # This follows the RFC: no double quotes around encoded values.
+        'rfc2231_encoded_no_double_quotes': (
+            ("text/plain;"
+                "\tname*0*=''This%20is%20;"
+                "\tname*1*=%2A%2A%2Afun%2A%2A%2A%20;"
+                '\tname*2="is it not.pdf"'),
+            'text/plain',
+            'text',
+            'plain',
+            {'name': 'This is ***fun*** is it not.pdf'},
+            [],
+            'text/plain; name="This is ***fun*** is it not.pdf"',
+            ('Content-Type: text/plain;\tname*0*=\'\'This%20is%20;\n'
+             '\tname*1*=%2A%2A%2Afun%2A%2A%2A%20;\tname*2="is it not.pdf"\n'),
+            ),
+
+        # Make sure we also handle it if there are spurrious double qoutes.
+        'rfc2231_encoded_with_double_quotes': (
+            ("text/plain;"
+                '\tname*0*="us-ascii\'\'This%20is%20even%20more%20";'
+                '\tname*1*="%2A%2A%2Afun%2A%2A%2A%20";'
+                '\tname*2="is it not.pdf"'),
+            'text/plain',
+            'text',
+            'plain',
+            {'name': 'This is even more ***fun*** is it not.pdf'},
+            [errors.InvalidHeaderDefect]*2,
+            'text/plain; name="This is even more ***fun*** is it not.pdf"',
+            ('Content-Type: text/plain;\t'
+                'name*0*="us-ascii\'\'This%20is%20even%20more%20";\n'
+             '\tname*1*="%2A%2A%2Afun%2A%2A%2A%20";\tname*2="is it not.pdf"\n'),
+            ),
+
+        'rfc2231_single_quote_inside_double_quotes': (
+            ('text/plain; charset=us-ascii;'
+               '\ttitle*0*="us-ascii\'en\'This%20is%20really%20";'
+               '\ttitle*1*="%2A%2A%2Afun%2A%2A%2A%20";'
+               '\ttitle*2="isn\'t it!"'),
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'us-ascii', 'title': "This is really ***fun*** isn't it!"},
+            [errors.InvalidHeaderDefect]*2,
+            ('text/plain; charset="us-ascii"; '
+               'title="This is really ***fun*** isn\'t it!"'),
+            ('Content-Type: text/plain; charset=us-ascii;\n'
+             '\ttitle*0*="us-ascii\'en\'This%20is%20really%20";\n'
+             '\ttitle*1*="%2A%2A%2Afun%2A%2A%2A%20";\ttitle*2="isn\'t it!"\n'),
+            ),
+
+        'rfc2231_single_quote_in_value_with_charset_and_lang': (
+            ('application/x-foo;'
+                "\tname*0*=\"us-ascii'en-us'Frank's\"; name*1*=\" Document\""),
+            'application/x-foo',
+            'application',
+            'x-foo',
+            {'name': "Frank's Document"},
+            [errors.InvalidHeaderDefect]*2,
+            'application/x-foo; name="Frank\'s Document"',
+            ('Content-Type: application/x-foo;\t'
+                'name*0*="us-ascii\'en-us\'Frank\'s";\n'
+             ' name*1*=" Document"\n'),
+            ),
+
+        'rfc2231_single_quote_in_non_encoded_value': (
+            ('application/x-foo;'
+                "\tname*0=\"us-ascii'en-us'Frank's\"; name*1=\" Document\""),
+            'application/x-foo',
+            'application',
+            'x-foo',
+            {'name': "us-ascii'en-us'Frank's Document"},
+            [],
+            'application/x-foo; name="us-ascii\'en-us\'Frank\'s Document"',
+            ('Content-Type: application/x-foo;\t'
+                'name*0="us-ascii\'en-us\'Frank\'s";\n'
+             ' name*1=" Document"\n'),
+             ),
+
+        'rfc2231_no_language_or_charset': (
+            'text/plain; NAME*0*=english_is_the_default.html',
+            'text/plain',
+            'text',
+            'plain',
+            {'name': 'english_is_the_default.html'},
+            [errors.InvalidHeaderDefect],
+            'text/plain; NAME="english_is_the_default.html"'),
+
+        'rfc2231_encoded_no_charset': (
+            ("text/plain;"
+                '\tname*0*="\'\'This%20is%20even%20more%20";'
+                '\tname*1*="%2A%2A%2Afun%2A%2A%2A%20";'
+                '\tname*2="is it.pdf"'),
+            'text/plain',
+            'text',
+            'plain',
+            {'name': 'This is even more ***fun*** is it.pdf'},
+            [errors.InvalidHeaderDefect]*2,
+            'text/plain; name="This is even more ***fun*** is it.pdf"',
+            ('Content-Type: text/plain;\t'
+                'name*0*="\'\'This%20is%20even%20more%20";\n'
+             '\tname*1*="%2A%2A%2Afun%2A%2A%2A%20";\tname*2="is it.pdf"\n'),
+            ),
+
+        # XXX: see below...the first name line here should be *0 not *0*.
+        'rfc2231_partly_encoded': (
+            ("text/plain;"
+                '\tname*0*="\'\'This%20is%20even%20more%20";'
+                '\tname*1*="%2A%2A%2Afun%2A%2A%2A%20";'
+                '\tname*2="is it.pdf"'),
+            'text/plain',
+            'text',
+            'plain',
+            {'name': 'This is even more ***fun*** is it.pdf'},
+            [errors.InvalidHeaderDefect]*2,
+            'text/plain; name="This is even more ***fun*** is it.pdf"',
+            ('Content-Type: text/plain;\t'
+                'name*0*="\'\'This%20is%20even%20more%20";\n'
+             '\tname*1*="%2A%2A%2Afun%2A%2A%2A%20";\tname*2="is it.pdf"\n'),
+            ),
+
+        'rfc2231_partly_encoded_2': (
+            ("text/plain;"
+                '\tname*0*="\'\'This%20is%20even%20more%20";'
+                '\tname*1="%2A%2A%2Afun%2A%2A%2A%20";'
+                '\tname*2="is it.pdf"'),
+            'text/plain',
+            'text',
+            'plain',
+            {'name': 'This is even more %2A%2A%2Afun%2A%2A%2A%20is it.pdf'},
+            [errors.InvalidHeaderDefect],
+            'text/plain; name="This is even more %2A%2A%2Afun%2A%2A%2A%20is it.pdf"',
+            ('Content-Type: text/plain;\t'
+                'name*0*="\'\'This%20is%20even%20more%20";\n'
+             '\tname*1="%2A%2A%2Afun%2A%2A%2A%20";\tname*2="is it.pdf"\n'),
+            ),
+
+        'rfc2231_unknown_charset_treated_as_ascii': (
+            "text/plain; name*0*=bogus'xx'ascii_is_the_default",
+            'text/plain',
+            'text',
+            'plain',
+            {'name': 'ascii_is_the_default'},
+            [],
+            'text/plain; name="ascii_is_the_default"'),
+
+        'rfc2231_bad_character_in_charset_parameter_value': (
+            "text/plain; charset*=ascii''utf-8%E2%80%9D",
+            'text/plain',
+            'text',
+            'plain',
+            {'charset': 'utf-8\uFFFD\uFFFD\uFFFD'},
+            [errors.UndecodableBytesDefect],
+            'text/plain; charset="utf-8\uFFFD\uFFFD\uFFFD"'),
+
+        'rfc2231_encoded_then_unencoded_segments': (
+            ('application/x-foo;'
+                '\tname*0*="us-ascii\'en-us\'My";'
+                '\tname*1=" Document";'
+                '\tname*2=" For You"'),
+            'application/x-foo',
+            'application',
+            'x-foo',
+            {'name': 'My Document For You'},
+            [errors.InvalidHeaderDefect],
+            'application/x-foo; name="My Document For You"',
+            ('Content-Type: application/x-foo;\t'
+                'name*0*="us-ascii\'en-us\'My";\n'
+             '\tname*1=" Document";\tname*2=" For You"\n'),
+            ),
+
+        # My reading of the RFC is that this is an invalid header.  The RFC
+        # says that if charset and language information is given, the first
+        # segment *must* be encoded.
+        'rfc2231_unencoded_then_encoded_segments': (
+            ('application/x-foo;'
+                '\tname*0=us-ascii\'en-us\'My;'
+                '\tname*1*=" Document";'
+                '\tname*2*=" For You"'),
+            'application/x-foo',
+            'application',
+            'x-foo',
+            {'name': 'My Document For You'},
+            [errors.InvalidHeaderDefect]*3,
+            'application/x-foo; name="My Document For You"',
+            ("Content-Type: application/x-foo;\tname*0=us-ascii'en-us'My;\t"
+                # XXX: the newline is in the wrong place, come back and fix
+                # this when the rest of tests pass.
+                'name*1*=" Document"\n;'
+             '\tname*2*=" For You"\n'),
+            ),
+
+        # XXX: I would say this one should default to ascii/en for the
+        # "encoded" segment, since the the first segment is not encoded and is
+        # in double quotes, making the value a valid non-encoded string.  The
+        # old parser decodes this just like the previous case, which may be the
+        # better Postel rule, but could equally result in borking headers that
+        # intentially have quoted quotes in them.  We could get this 98% right
+        # if we treat it as a quoted string *unless* it matches the
+        # charset'lang'value pattern exactly *and* there is at least one
+        # encoded segment.  Implementing that algorithm will require some
+        # refactoring, so I haven't done it (yet).
+
+        'rfc2231_qouted_unencoded_then_encoded_segments': (
+            ('application/x-foo;'
+                '\tname*0="us-ascii\'en-us\'My";'
+                '\tname*1*=" Document";'
+                '\tname*2*=" For You"'),
+            'application/x-foo',
+            'application',
+            'x-foo',
+            {'name': "us-ascii'en-us'My Document For You"},
+            [errors.InvalidHeaderDefect]*2,
+            'application/x-foo; name="us-ascii\'en-us\'My Document For You"',
+            ('Content-Type: application/x-foo;\t'
+                'name*0="us-ascii\'en-us\'My";\n'
+             '\tname*1*=" Document";\tname*2*=" For You"\n'),
+            ),
+
+    }
+
+
+@parameterize
+class TestContentTransferEncoding(TestHeaderBase):
+
+    def cte_as_value(self,
+                     source,
+                     cte,
+                     *args):
+        l = len(args)
+        defects =  args[0] if l>0 else []
+        decoded =  args[1] if l>1 and args[1] is not DITTO else source
+        header = 'Content-Transfer-Encoding:' + ' ' if source else ''
+        folded = args[2] if l>2 else header + source + '\n'
+        h = self.make_header('Content-Transfer-Encoding', source)
+        self.assertEqual(h.cte, cte)
+        self.assertDefectsEqual(h.defects, defects)
+        self.assertEqual(h, decoded)
+        self.assertEqual(h.fold(policy=policy.default), folded)
+
+    cte_params = {
+
+        'RFC_2183_1': (
+            'base64',
+            'base64',),
+
+        'no_value': (
+            '',
+            '7bit',
+            [errors.HeaderMissingRequiredValue],
+            '',
+            'Content-Transfer-Encoding:\n',
+            ),
+
+        'junk_after_cte': (
+            '7bit and a bunch more',
+            '7bit',
+            [errors.InvalidHeaderDefect]),
+
+    }
+
+
+@parameterize
+class TestContentDisposition(TestHeaderBase):
+
+    def content_disp_as_value(self,
+                              source,
+                              content_disposition,
+                              *args):
+        l = len(args)
+        parmdict = args[0] if l>0 else {}
+        defects =  args[1] if l>1 else []
+        decoded =  args[2] if l>2 and args[2] is not DITTO else source
+        header = 'Content-Disposition:' + ' ' if source else ''
+        folded = args[3] if l>3 else header + source + '\n'
+        h = self.make_header('Content-Disposition', source)
+        self.assertEqual(h.content_disposition, content_disposition)
+        self.assertEqual(h.params, parmdict)
+        self.assertDefectsEqual(h.defects, defects)
+        self.assertEqual(h, decoded)
+        self.assertEqual(h.fold(policy=policy.default), folded)
+
+    content_disp_params = {
+
+        # Examples from RFC 2183.
+
+        'RFC_2183_1': (
+            'inline',
+            'inline',),
+
+        'RFC_2183_2': (
+            ('attachment; filename=genome.jpeg;'
+             '  modification-date="Wed, 12 Feb 1997 16:29:51 -0500";'),
+            'attachment',
+            {'filename': 'genome.jpeg',
+             'modification-date': 'Wed, 12 Feb 1997 16:29:51 -0500'},
+            [],
+            ('attachment; filename="genome.jpeg"; '
+                 'modification-date="Wed, 12 Feb 1997 16:29:51 -0500"'),
+            ('Content-Disposition: attachment; filename=genome.jpeg;\n'
+             '  modification-date="Wed, 12 Feb 1997 16:29:51 -0500";\n'),
+            ),
+
+        'no_value': (
+            '',
+            None,
+            {},
+            [errors.HeaderMissingRequiredValue],
+            '',
+            'Content-Disposition:\n'),
+
+        'invalid_value': (
+            'ab./k',
+            'ab.',
+            {},
+            [errors.InvalidHeaderDefect]),
+
+        'invalid_value_with_params': (
+            'ab./k; filename="foo"',
+            'ab.',
+            {'filename': 'foo'},
+            [errors.InvalidHeaderDefect]),
+
+    }
+
+
+@parameterize
+class TestMIMEVersionHeader(TestHeaderBase):
+
+    def version_string_as_MIME_Version(self,
+                                       source,
+                                       decoded,
+                                       version,
+                                       major,
+                                       minor,
+                                       defects):
+        h = self.make_header('MIME-Version', source)
+        self.assertEqual(h, decoded)
+        self.assertEqual(h.version, version)
+        self.assertEqual(h.major, major)
+        self.assertEqual(h.minor, minor)
+        self.assertDefectsEqual(h.defects, defects)
+        if source:
+            source = ' ' + source
+        self.assertEqual(h.fold(policy=policy.default),
+                        'MIME-Version:' + source + '\n')
+
+    version_string_params = {
+
+        # Examples from the RFC.
+
+        'RFC_2045_1': (
+            '1.0',
+            '1.0',
+            '1.0',
+            1,
+            0,
+            []),
+
+        'RFC_2045_2': (
+            '1.0 (produced by MetaSend Vx.x)',
+            '1.0 (produced by MetaSend Vx.x)',
+            '1.0',
+            1,
+            0,
+            []),
+
+        'RFC_2045_3': (
+            '(produced by MetaSend Vx.x) 1.0',
+            '(produced by MetaSend Vx.x) 1.0',
+            '1.0',
+            1,
+            0,
+            []),
+
+        'RFC_2045_4': (
+            '1.(produced by MetaSend Vx.x)0',
+            '1.(produced by MetaSend Vx.x)0',
+            '1.0',
+            1,
+            0,
+            []),
+
+        # Other valid values.
+
+        '1_1': (
+            '1.1',
+            '1.1',
+            '1.1',
+            1,
+            1,
+            []),
+
+        '2_1': (
+            '2.1',
+            '2.1',
+            '2.1',
+            2,
+            1,
+            []),
+
+        'whitespace': (
+            '1 .0',
+            '1 .0',
+            '1.0',
+            1,
+            0,
+            []),
+
+        'leading_trailing_whitespace_ignored': (
+            '  1.0  ',
+            '  1.0  ',
+            '1.0',
+            1,
+            0,
+            []),
+
+        # Recoverable invalid values.  We can recover here only because we
+        # already have a valid value by the time we encounter the garbage.
+        # Anywhere else, and we don't know where the garbage ends.
+
+        'non_comment_garbage_after': (
+            '1.0 <abc>',
+            '1.0 <abc>',
+            '1.0',
+            1,
+            0,
+            [errors.InvalidHeaderDefect]),
+
+        # Unrecoverable invalid values.  We *could* apply more heuristics to
+        # get someing out of the first two, but doing so is not worth the
+        # effort.
+
+        'non_comment_garbage_before': (
+            '<abc> 1.0',
+            '<abc> 1.0',
+            None,
+            None,
+            None,
+            [errors.InvalidHeaderDefect]),
+
+        'non_comment_garbage_inside': (
+            '1.<abc>0',
+            '1.<abc>0',
+            None,
+            None,
+            None,
+            [errors.InvalidHeaderDefect]),
+
+        'two_periods': (
+            '1..0',
+            '1..0',
+            None,
+            None,
+            None,
+            [errors.InvalidHeaderDefect]),
+
+        '2_x': (
+            '2.x',
+            '2.x',
+            None,  # This could be 2, but it seems safer to make it None.
+            None,
+            None,
+            [errors.InvalidHeaderDefect]),
+
+        'foo': (
+            'foo',
+            'foo',
+            None,
+            None,
+            None,
+            [errors.InvalidHeaderDefect]),
+
+        'missing': (
+            '',
+            '',
+            None,
+            None,
+            None,
+            [errors.HeaderMissingRequiredValue]),
+
+        }
+
+
+@parameterize
 class TestAddressHeader(TestHeaderBase):
 
     example_params = {