Ghostscript is now distributed in two different versions, with two
different licenses.  The current version with the GNU License is in
the gnu subdirectory; the current version with the new Aladdin
Free Public License is in the AFPL subdirectory.  The
AFPL version will typically be about a year more recent than the
GNU version; however, the AFPL license, unlike the GNU license, 
prohibits all commercial distribution (unless you get a commercial
license from Artifex Software Inc., which is currently the only entity
authorized by artofcode LLC to grant such licenses.)  For more information,
please read the file Commprod.htm in the AFPL directory.  For a
copy of the AFPL license, see the file PUBLIC in the AFPL directory.

The directory AFPL/current is a link to the most recent version
of AFPL Ghostscript.
Instructions on how to obtain AFPL Ghostscript are available from
   http://www.cs.wisc.edu/~ghost/

GSview for Windows, OS/2 and Linux are also distributed with a
similar pair of licenses, even though they are not part of Ghostscript
and their copyright is owned by Ghostgum Software Pty Ltd, 
not artofcode LLC.
The code that allows Ghostscript to function as a DLL under MS Windows
and OS/2 is also owned by Ghostgum Software Pty Ltd.
They are designed to work with AFPL Ghostscript, not GNU Ghostscript.

The files in the 3rdparty directory are libraries used by
Ghostscript (JPEG, libpng and zlib).  They are a copy of the versions 
available on many file servers around the net.  Since Ghostscript versions 
3.0 and above use these libraries, we thought it would be a good idea to 
keep a copy near the principal Ghostscript distribution point.