diff -r 8c55fb5a11d8 Doc/library/typing.rst
--- a/Doc/library/typing.rst	Sun Aug 09 23:23:21 2015 -0400
+++ b/Doc/library/typing.rst	Mon Aug 10 22:13:40 2015 -0500
@@ -352,31 +352,76 @@
 
 .. class:: MutableSequence(Sequence[T])
 
+   A generic version of :class:`collections.abc.MutableSequence`.
+
 .. class:: ByteString(Sequence[int])
 
+   An abstract base class of :class:`collections.abc.ByteString`.
+
+   This type represents the types `bytes`, `bytearray`, and `memoryview`.
+
+   As a shorthand for this type, `bytes` can be used to annotate arguments of
+   any of the types mentioned above.
+
 .. class:: List(list, MutableSequence[T])
 
-.. class:: Set(set, MutableSet[T])
+   Useful for annotating return types. To annotate arguments it is preferred
+   to use abstract collection types such as :class:`Mapping`, :class:`Sequence`,
+   or :class:`AbstractSet`.
+
+   This type may be used as follows::
+
+      T = TypeVar('T', int, float)
+
+      def vec2(x: T, y: T) -> List[T]:
+          return [x, y]
+
+      def slice__to_4(vector: Sequence[T]) -> List[T]:
+          return vector[0:4]
+
+.. class:: AbstractSet(set, MutableSet[T])
+
+   An abstract base class of :class:`collections.abc.Set`.
 
 .. class:: MappingView(Sized, Iterable[T_co])
 
+   An abstract base class of :class:`collections.abc.MappingView`.
+
 .. class:: KeysView(MappingView[KT_co], AbstractSet[KT_co])
 
+   An abstract base class of :class:`collections.abc.KeysView`.
+
 .. class:: ItemsView(MappingView, Generic[KT_co, VT_co])
 
+   An abstract base class of :class:`collections.abc.ItemsView`.
+
 .. class:: ValuesView(MappingView[VT_co])
 
+   An abstract base class of :class:`collections.abc.ValuesView`.
+
 .. class:: Dict(dict, MutableMapping[KT, VT])
 
+   Dictionary type that inherits from :class:`MutableMapping`.
+
+   The usage of this type is as follows::
+
+      def get_position_in_index(word_list: Dict[str, int], word: str) -> int:
+          return word_list[word]
+
 .. class:: Generator(Iterator[T_co], Generic[T_co, T_contra, V_co])
 
 .. class:: io
 
-   Wrapper namespace for IO generic classes.
+   Generic base class for TextIO and BinaryIO.
+
+   Only the types IO[str], IO[bytes], and IO[Any] and the aliases
+   TextIO, BinryIO, and IO respectively are valid.
 
 .. class:: re
 
-   Wrapper namespace for re type classes.
+   Generic base class for the Match and Pattern types.
+
+   The types Pattern[Any] and Match[Any] are valid within the re submodule.
 
 .. function:: NamedTuple(typename, fields)