The Showtime television series Dexter, which is based on Jeff Lindsay's books, was such a hit in its first season that it has been renewed for a second.
Lindsay's protagonist, Dexter Morgan, is a blood-splatter analyst for the Miami-Dade Police Department who is a serial killer in his spare time.
The good news is that he only kills criminals who have managed to escape justice.
Dexter is driven by his "Dark Passenger" - a sort of alter ego - who prompts him to even scores for the common good.
The TV episodes portray the graphic violence of the books, for sure, but also capture what BookPage calls Lindsay's "ever so slightly highbrow" tone -- a tongue-in-cheek style similar to Lawrence Block's Bernie Rhodenbarr series, displaying "an endearingly self-effacing quality in the protagonist."
Bernie is a Greenwich Village bookseller who can't resist a little breaking-and-entering now and then and often develops obsessions, such as his "Morton's Foot" condition. Nothing as dark as avenging inner spirits, however.
There are three Dexter novels, the third of which is the recently released Dexter in the Dark. Publishers Weekly promises that "the macabre wit that powered the first two installments ... is still evident."