From the introduction:
This book is intended for use in a fantasy setting, in a region long settled by humans that have a well established pantheistic religion. The inhabitants of this region worship a society of deities, with each god representing particular aspects of the lives of mortals. Many of the gods are related by blood, having descended from a small group of ancient powers, and most have their own particular allies and foes among the pantheon.
This book has a long history, beginning with a mid-1990s 1st Edition version. The document was converted to 3rd Edition with Version 6, in 2001.