This is what I might call "an oddly interesting book". I say that because in retrospect I'm a bit surprised that it holds the interest so well. Mr. Ronson begins with a strange little mystery concerning running down the source/writer of an (to use the same word) odd book that has been mailed to certain people. From this the book springboards into a look at Psychopathy, its diagnosis and by extension the way in which psychiatric disorders are not only diagnosed but agreed on (that is agreed to exist as disorders).
Rambling a bit and full of introspective thoughts by the author (most of which are interesting and entertaining if not always germane) we go through a series of interviews that range from "Tony" to Bob Hare who basically formulated the most used Psychopath test. Tony was a young man who has been in Broadmoor for years, sent there after a relatively minor offense. The author was brought there by representatives of the church of Scientology in an attempt to discredit psychiatry in general. Other interviews included Emmanuel Constant, a former Haitian death-squad leader. He also interviewed a corporate hatchet man type exec. who was know for blithely firing people and joyously shutting down plants.
There is a lot that's interesting here and the book will (I believe) keep you involved. After looking into how disorders get into (and are pulled out of) DSM-IV-TR, considering the implications of Hare's list (and how it effected the author as he found himself setting out to find and identify "free range psychopaths) and the attitudes around these he came to an interesting conclusion. That they may be dangerous tools leading to over diagnosis.
I suggest you take a look at this, especially if you (like me) have been "concerned" about statements like "1% to 10% of the population may be psychopaths". While this book may be a bit more disjointed than some of the author's other works...it's well done and interesting.