Dearly Devoted Dexter is much darker than the first Dexter book. Maybe it is just because all the facts about Dexter are clear and it starts with a gruesome murder, insane special forces style. The title comes from the fact that he helps his sister, now partially in the loop about his Dark Passenger, to solve the newest serial killer case. Of course, Deb, now a seargent after Laguerta has died, has a personal stake in this, since one of the people the murderer abducted and intends to do bad things to, is her boyfriend, with whom she is very much in love.
It is interesting to develop the Dexter character in this way, especially since he is described as totally indifferent to the horrible fate of people he doesn't care about, yet he is still compelled to help his sister out.
I was a bit disapointed by the police work involved. If I were to believe Lindsay, the Miami police are a bunch of morons, following (badly) a set of procedures without any real talent other than badmouthing.
Elements from this second book in the Dexter series were clearly used in the series, but it is already a completely different story. The FBI agent that Deborah briefly dates in the series was inspired by the character of Kyle, shady government agent that she falls in love with in this book. The stalking of Dexter by the grumpy seargent Doakes is also mirrored from this book, although the motives and the outcome are completely different.
Again, the series evolves the Dexter character more and the story is more complex than the book, but by now it is obvious the TV show and the book are going in completely different directions.
All in all, a bit better than the first, darker, but also funnier. I have never laughed as much reading a book for a long time. Can't wait for the third book now.