Dexter Morgan is a serial killer with a code; his targets: other serial killers.
What is it about Dexter that makes him (almost) likable?
For information about the author and other books in the series, check out:
http://www.dexter-books.com/bios/jeff-lindsay
For an interesting article about the character of Dexter (in the books and in the Showtime series), check out:
http://www.rhombusmag.com/2011/02/09/tv-darkly-dreaming-dexter-why-we-root-for-a-serial-killer/