If you know your Fortean History, this is an old story, told in various tomes. The book is a little bit padded with explanations of what possession is and what it is not. The retelling of the story from the orignal sources strays into lame cliches.

Even for what this book is, I enjoyed it. I think it would have far better to reprint the initial WATSEKA WONDER material (described as a pamphelt) and annotate it.

For those of you who never heard this tale, this is a good place to start.