Also, the first sentences of third paragraph have some problems:

> For both the Unix and Windows versions of the constructor,
> access may be specified as an optional keyword
> parameter. access accepts one of four values: ACCESS_READ,
> ACCESS_WRITE, or ACCESS_COPY to specify read-only,
> write-through or copy-on-write memory respectively, or
> ACCESS_DEFAULT to defer to prot. access can be used on both
> Unix and Windows. If access is not specified, Windows mmap
> returns a write-through mapping.

1. It redundantly says that *access* may be used for Unix and Windows.
2. It says ACCESS_DEFAULT defers to *prot* but doesn't say this is only for Unix nor that *prot* is a parameter.
3. It doesn't say what happens on Unix if *access* is not specified except implicitly by the earlier statement about ACCESS_DEFAULT.

Proposed change:

    For both the Unix and Windows versions of the constructor,
    *access* may be specified as an optional keyword parameter.
    *access* accepts one of the four :ref:`ACCESS_* constants
    <access-constants>`: :const:`ACCESS_READ`,
    :const:`ACCESS_WRITE`, or :const:`ACCESS_COPY` to specify
    read-only, write-through or copy-on-write memory
    respectively, or :const:`ACCESS_DEFAULT` (the default value
    if *access* is not specified) to return a write-through
    mapping on Windows or defer to the value of the *prot*
    parameter on Unix.