The secrets of the spirit world unveiled for the first time!
This supplement came out when AD&D was seriously winding down. White Wolf was kicking their ass without a doubt. It introduced the spirit world, and three classes that gained their power from it. Saying three new classes was a little misleading, it was more like one new class, three kits.
The new classes were a little like priests, but when they chose spells for their spell slots, it was permanent. If they wanted to switch out a spell it would offend their patron spirit. Most of the spells dealt exclusively with spirits. One gave the shaman the ability to bind spirits into fetishes.
Pretty pointless supplement. In the DM only section, it is revealed that the spirit world doesn't exist. It's all in the heads of the shaman. Stupid. Integrating this into a running campaign would assuredly end it. Starting a new campaign based on this would turn into one guy is the hero, everyone else follows him around as he reads omens and barters with ancestors.