This is a very well-researched book that explores the biological, psychological, and social reasons that people join cults. In addition to examining groups that are commonly thought of as cults (such as the Moonies), the author also looks at groups that have cult-like behaviors, such as Alcoholics Anonymous.
If you are just beginning to research cults, then this book is a good introduction to the subject. It's very thorough. The author has a lot of experience with these groups and obviously knows what he's talking about. I appreciate that he approached the subject objectively. He doesn't assume that all cults are evil and that all people should conform to the beliefs of mainstream society. I also like how the book discusses the conflicts between cults and society in an objective way. Many books only look at a cult's behavior and ignore the society in which it exists.
If you aren't new to cult research, then there's nothing stunning about this book. The writing style is fairly dry. If you've done enough research, you've probably already come to many of the same conclusions as the author. However, I still thought the book was pretty fascinating. It's worth reading.