From the back of the book:
Campaign Sourcebook
Enter the world developed by award-winning fantasy artist Larry Elmore and made famous by Margaret Weis & Tracy Hickman in the best-selling Sovereign Stone novel trilogy from HarperCollins Publishers.
Sovereign Stone is a complete campaign setting for the fabulous d20 system. Included are new races, new classes, new feats, new skills, new monsters-created by some of the best known names in the RPG industry.
Learn to cast magic in a new way in the Sovereign Stone world. A new d20 magic system lets you build points toward the casting of spells, making complex spells more difficult to cast, while simple spells are easy and quick.
The world has Orks, Elves, Humans and Dwarves as player races, powerful Dominion Lords who fight for good against the evil undead knights of the Void.
The Orks are a sea-faring races, advantaged in Water magic. The Elves have a culture similar to medieval Japan and are advantaged in Air magic. The Dwarves are a nomadic people similar to the Mongols, and are advantaged in Fire magic. There are a half-dozen distinct Human cultures, all advantaged in Earth magic. The Taan, Void magic-users, are a mysterious race bent on conquering the rest!