Everything you need to be able to develop GEOS programs/libraries/etc.
except for Borland C/C++ v3.1 or v4.x. It's got all of the documentation
online (in at least three different formats), the assembler, linker, GOC,
pmake, sample code, etc. It's got both optimized and debugging versions of
the system and multiple UIs so you can test your stuff under various SPUIs.
Hope this helps,
John "1-800-GEOS-SDK" Mitchell