From the Introduction:
Dark Sun 3 is a new edition of the Dark Sun campaign setting, written using the Dungeons & Dragons 3.5 rules. You will need the Player’s Handbook (PH), Dungeon Master’s Guide (DMG), Monster Manual (MM), and the Expanded Psionics Handbook (XPH) to make use of the material in this book. In addition, you might find useful to download the Athasian Emporium (AE), Terrors of Athas (ToA), Terrors of the Dead Lands (TotDL), and Faces of the Forgotten North (FFN), since this book contains a small amount of material presented in those rulebooks.
This document is intended for an audience already familiar with the Dark Sun campaign setting, and does not attempt to detail the world of Athas in full. For more information on Athas, visit www.athas.org – the official Dark Sun website. In addition to the latest version of this document, you may find other Dark Sun material available as free downloads.