diff --git a/Doc/library/re.rst b/Doc/library/re.rst
index b4e0557..07868b2 100644
--- a/Doc/library/re.rst
+++ b/Doc/library/re.rst
@@ -417,6 +417,9 @@
    \r      \t      \v      \x
    \\
 
+(Note that ``\b`` is used to represent word boundaries, and means "backspace"
+only inside character classes.)
+
 Octal escapes are included in a limited form.  If the first digit is a 0, or if
 there are three octal digits, it is considered an octal escape. Otherwise, it is
 a group reference.  As for string literals, octal escapes are always at most