Standardise on sentence case for titles
diff --git a/docs/development/custom-vectors/cast5.rst b/docs/development/custom-vectors/cast5.rst
index f540027..98c5ba7 100644
--- a/docs/development/custom-vectors/cast5.rst
+++ b/docs/development/custom-vectors/cast5.rst
@@ -1,4 +1,4 @@
-CAST5 Vector Creation
+CAST5 vector creation
 =====================
 
 This page documents the code that was used to generate the CAST5 CBC, CFB, OFB,
diff --git a/docs/development/custom-vectors/idea.rst b/docs/development/custom-vectors/idea.rst
index 68c00b8..e0db58d 100644
--- a/docs/development/custom-vectors/idea.rst
+++ b/docs/development/custom-vectors/idea.rst
@@ -1,4 +1,4 @@
-IDEA Vector Creation
+IDEA vector creation
 =====================
 
 This page documents the code that was used to generate the IDEA CBC, CFB, and
diff --git a/docs/development/getting-started.rst b/docs/development/getting-started.rst
index 412f054..3d9012e 100644
--- a/docs/development/getting-started.rst
+++ b/docs/development/getting-started.rst
@@ -1,4 +1,4 @@
-Getting Started
+Getting started
 ===============
 
 Working on ``cryptography`` requires the installation of a small number of
@@ -14,7 +14,7 @@
 
 You are now ready to run the tests and build the documentation.
 
-Running Tests
+Running tests
 ~~~~~~~~~~~~~
 
 ``cryptography`` unit tests are found in the ``tests/`` directory and are
@@ -49,7 +49,7 @@
 will see one or more ``InterpreterNotFound`` errors.
 
 
-Explicit Backend Selection
+Explicit backend selection
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 While testing you may want to run tests against a subset of the backends that
@@ -63,7 +63,7 @@
     $ tox -- --backend=openssl
     $ py.test --backend=openssl,commoncrypto
 
-Building Documentation
+Building documentation
 ~~~~~~~~~~~~~~~~~~~~~~
 
 ``cryptography`` documentation is stored in the ``docs/`` directory. It is
diff --git a/docs/development/reviewing-patches.rst b/docs/development/reviewing-patches.rst
index 302c998..9147a73 100644
--- a/docs/development/reviewing-patches.rst
+++ b/docs/development/reviewing-patches.rst
@@ -1,4 +1,4 @@
-Reviewing/Merging Patches
+Reviewing/merging patches
 =========================
 
 Everyone is encouraged to review open pull requests. When reviewing a patch try
@@ -32,7 +32,7 @@
 * Does a variable need a better name?
 * Should this be a keyword argument?
 
-Merge Requirements
+Merge requirements
 ------------------
 
 Because cryptography is so complex, and the implications of getting it wrong so
diff --git a/docs/development/submitting-patches.rst b/docs/development/submitting-patches.rst
index 1797b9c..f1bf954 100644
--- a/docs/development/submitting-patches.rst
+++ b/docs/development/submitting-patches.rst
@@ -1,4 +1,4 @@
-Submitting Patches
+Submitting patches
 ==================
 
 * Always make a new branch for your work.
@@ -29,7 +29,7 @@
 
     from __future__ import absolute_import, division, print_function
 
-API Considerations
+API considerations
 ~~~~~~~~~~~~~~~~~~
 
 Most projects' APIs are designed with a philosophy of "make easy things easy,
diff --git a/docs/development/test-vectors.rst b/docs/development/test-vectors.rst
index 1d76817..164d0ab 100644
--- a/docs/development/test-vectors.rst
+++ b/docs/development/test-vectors.rst
@@ -1,4 +1,4 @@
-Test Vectors
+Test vectors
 ============
 
 Testing the correctness of the primitives implemented in each ``cryptography``
@@ -10,7 +10,7 @@
 Sources
 -------
 
-Asymmetric Ciphers
+Asymmetric ciphers
 ~~~~~~~~~~~~~~~~~~
 
 * RSA PKCS #1 from the RSA FTP site (ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/
@@ -43,7 +43,7 @@
 * HMAC-RIPEMD160 from :rfc:`2286`.
 * HMAC-SHA2 (224, 256, 384, 512) from :rfc:`4231`.
 
-Key Derivation Functions
+Key derivation functions
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
 * HKDF (SHA1, SHA256) from :rfc:`5869`.
@@ -55,7 +55,7 @@
 
 * Fernet from its `specification repository`_.
 
-Symmetric Ciphers
+Symmetric ciphers
 ~~~~~~~~~~~~~~~~~
 
 * AES (CBC, CFB, ECB, GCM, OFB) from `NIST CAVP`_.
@@ -72,14 +72,14 @@
 * IDEA (CBC, CFB, OFB) generated by this project.
   See: :doc:`/development/custom-vectors/idea`
 
-Two Factor Authentication
+Two factor authentication
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 * HOTP from :rfc:`4226`
 * TOTP from :rfc:`6238` (Note that an `errata`_ for the test vectors in RFC
   6238 exists)
 
-Creating Test Vectors
+Creating test vectors
 ---------------------
 
 When official vectors are unavailable ``cryptography`` may choose to build