The creatures of the Other World are all around us. Some were once alive. Some were created by human imagination. And some are completely inhuman but thirst for our souls. GURPS Spirits is a complete guide to the spirit realm and its inhabitants. It includes a catalog of spirits from around the angels, demons, djinn, dryads, ghosts, loas, manitou, raksasha, and many, many more. It is also a campaign guide for characters who see spirits, serve them, use them . . . or fight them! Also an expanded version of the ritual magic rules first seen in GURPS Voodoo, as a system for spirit-mediated magic.
When I was younger, these quasi-anthropological GURPS books were some of my favorite RPG books. I can still see the appeal, but after years of education and reading, they are less useful to me than they once were. Like GURPS Faeries, I wish this one were longer so we could get a little more substance, especially since so much of the book was taken up with the magic system from GURPS Voodoo.