This book seems to be written out of a sincere wish to warn the world about the human predators among us. While it is true that some things are repeated that seems to me to be done in order to hammer the point home rather than to fill up space/pages. The author is also up front about the fact that it is almost impossible to spot a psychopath even though the title of the book suggest otherwise. The book is actually meant (I believe) to help people who suspect or know that they are victims of this kind of person to come to terms with it and save themselves. This may not be scholarly but it will save many abused people, I´m sure.
The book itself is quite well written and gets the point across in an easy to follow manner. Not because it is dumbed down but because the author writes clearly and with a certain purpose in mind.
I can see by the reviews here that this book has scared the psychopaths and this, to me, greatly recommends this book.
I want to say on slightly off topic thing before I leave. It is well known that abusive husbands/boyfriends will blame the couples problems on their spouse/girlfriend and accuse her of the very behavior he is guilty of. This often works and nets him all the support and pity that should go to his victim. These men are probably psychopaths.