A good wide coverage of both strange beliefs and the people behind them. He works methodically through such topics as holocaust denial, witch hunts and creationism.
Some surprising conclusions (which I won't spoil for you) as he tries to come up with the answer to the title of the book.
His style is simple and straightforward, matter of fact, and self revealing both in terms of his own past beliefs and by sharing situations where he was particularly ineffective in the face of believers.
He also shows you the human side of alien abductees and holocaust deniers alike - yes honestly.
If you are human then this book will tell you something about yourself as well. Believing in weird things goes with the territory and has some positive evolutionary advantages - so try to figure out what yours are.
3.5 out of five stars