Overall, I felt this book was a good one. It's obviously an interesting subject (though occasionally horrifying), and the author provides a great amount of detail and insight into the childhoods, early adulthood, and early murders of the subjects in question. Also included are some very telling quotations by the murderers themselves.
However, I felt that some of the author narrative was distracting and occasionally far-fetched. He seems to cling to the idea that these killers are 'two-sided', or, as he sometimes describes, Dr. Jekyll and Mr. Hyde. While it would certainly be comforting to think that there was a part of these individuals that was separate and untouched by their homicidal urges and sado-sexual impulses, I personally find it unlikely. The fact that John Gacy was an active and often productive member of society does not mean that the productive part of him was separated from the part that raped and killed teenage boys. We would all like to think that we would be able to tell someone with these sort of violent tendencies, but at least in Gacy's case, it was not evident at all to the individuals in the community he served. They valued, rewarded, and took pride in his place in their society and he often did things that were beneficial to the community at large. He also happened to be a murderer. I do not think that these things are mutually exclusive simply because we want them to be, because we want to believe that no community could love and praise a man who was killing their young boys. But there's little evidence to truly support such a claim, and the author stretches toward the idea that there are two Gacy's, the good and the evil one. Frankly, I found it to be grasping at straws. This theme of 'the evil side' seems to carry through to other murderers in the book, as well. It struck me more that the author is trying very hard to be clever, and while he often succeeds at sounding intelligent, well-informed, and plausible with his beliefs - there is the occasional moment of discord when he makes a statement that just doesn't seem right.
Aside from stylistic annoyances, though, I think the book was overall a great read and very compelling. It's a broad look at several serial killers, and the subjects chosen were particularly good for the purpose of the book. Covered are John Gacy, Kenneth Bianchi, William Heirens, John Cannan, and Patricia Wright. I would recommend it to people interested in knowing a bit more about this darker side of humanity. Of course, and I imagine this goes without saying, this may be a difficult read for people who have a low tolerance for violent imagery. Although the details of the crimes are quite appropriately clinical, one can't help envisioning them as they read and for that reason I wouldn't recommend it for the weak of heart.