Interesting book. Some valuable information about causality of different kinds of crime and the different characteristics of groups like rapists (usually men of European ethnicity, by the way). The last half of the book is all about Roy Hazelwood and his ability and success as a criminal profiler. I found that less interesting than the first few chapters.
Another reservation about the whole field of criminal profiling. There's no question that Hazelwood is brilliant at this, but he has a number of imitators in law enforcement that don't know what they're doing and are arrogant about applying what they think is his profiling system when they come upon a crime. The most egregious is the typing and subsequent media-mauling of Richard Jewell, a security guard in the Olympic Village in Atlanta in 1996. Jewell discovered a likely bomb on the grounds and alerted everyone to vacate the area. FBI profilers quickly concluded that Jewell was the bomber himself, and could tell by his need to be heroic in a crisis situation. He was convicted in the press, then later discovered not to have had anything to do with the bomb. He sued NBC for $500,000 after his exoneration, although he considered his life to have been ruined by the false accusations. He also sued his employer, Piedmont College, and a few other media. After his exoneration (the bomber turned out to be Eric Rudolph) Jewell was feted and awarded, but the damage had already been done by innuendo.
Another case, in Dave Eggers' book Surviving Justice: America's Wrongfully Convicted, one of the narratives concerns a cop who determined by his individual profiling system that a certain woman had to be guilty of a crime. His profiling caused him to overlook the actual clues and facts of the crime, and the woman was sent to jail.
Those two cases are just extensions of the profiling system and have nothing to do with Hazelwood, but it shows an alarming trend of amateur profilers falsely identifying "criminals" based solely on the profiling system they have cobbled together. It's just a tangential subject to this book, but it shows how a little knowledge is a dangerous thing.
Also, a warning to readers of this book: There are stories with specifics so gruesome and perverted that they are difficult to get through.