I enjoyed 'Sleepyhead' but I enjoyed this one even more. Thorne is an interesting character, he wants to do the best job he can regardless of the consequences.
The basic premise of the story is one that has been done before (2 killers working in tandem), but has a unique spin on it, it looks at how a child becomes a killer and the effect fear has on people.
The characters of Thorne, Hendricks and Holland are nicely developed. At the start I was slightly concerned at some of the language used ("the sky was the colour of a long dead fish", WTF???), but it got better. I did feel that it finished somewhat abruptly. But I'll definately be continuing with the Thorne books.