This is the second Dexter book by Jeff Lindsay.
Well! The second season of the show was rather a departure from the second book! About the only similarity is that Doakes is following Dexter around and not letting him do his thing. Other than that... majorly different!
This one was a lot darker than the first book. Which, considering the subject matter, is saying something. There's a bad guy running around doing truly horrible things to people, but he leaves them alive (but completely ruined and insane) when he's done with them. And somehow Doakes' past is involved.
Dexter does some serious bonding with the kids, which I like. His whole "I'm not human" thing kind of falls apart when kids are involved. Of course this isn't normal bonding, since this is Dexter, but that kind of goes with the territory.