Interesting read. This guy was at the heart of the development of the profiling unit of the FBI, and reading about how he developed his techniques for understanding the mind of a serial killer (largely a process of semi-educated trial and error) was pretty fascinating. I don't know how much his co-author was involved, because the vernacular style of the narrative (and the tendency to jump around a good deal) felt like the voice of an individual, and one not all that polished in the writing department at that.
The other thing I found intriguing about the book is how many of the cases he talked about seem to have inspired episodes of the CBS TV show Criminal Minds
(at least three that I noted) - not exact retellings, but using the underlying facts: for instance, the story of Shari Smith, where the killer made contact with her sister Dawn and indicated he planned to do the same to her; this was recast for TV as identical twin sisters, one of whom was kidnapped, and the kidnapper contacted the other twin and tried to grab her as well. Chilling stuff, when you remind yourself it's not fiction.