While the title sounds like a mystery novel or a "Made for TV Movie", the book is a dynamic powerhouse of this previously neglected part of Crowley's life. It details not only his personal use of the talking board, but also his willingness to teach responsible people how to use it with great effect and safety.
The book is written by, and largely for ceremonial magicians by Red Flame member, J. Edward Cornelius. While it is helpful for traditions outside of the OTO, it is tailored to be used in that magickal context and it's traditional methods. It is not an exposure of their practices, but rather how to plug that into traditions of the Golden Dawn, OTO, Gnostic Catholic Church, et al..it is not a book for conspiracy theorists!
The books one fault is that it takes a patronizing approach to Wicca and witchcraft throughout its contents. But by letting that go, it does give a very useful approach to using the board for spirit commincation, and makes clear the potential for harm that comes with the board. I highly reccomend it for Crowley fans, divination enthusist, and the witch and magician at large.