Although Jeff Lindsay's third Dexter novel does have some of the style that made the first two enjoyable there is an irritating strand that converts this entry in the series from a crime novel to a fantasy and a somewhat trite fantasy at that. Dexter, the artificial human being, in the sense that his apparent humanity is entirely a work of artifice, continues his twin careers as serial killer of deserving victims and Miami police blood splatter specialist and adds a third as mentor and guide to the burgeoning appetites of his fiancee's children. A pair of monsters in the making. So far so good. What spoils the book is the characterisation of the serial killing tendency as something truly external. Dexter has always talked of his Dark Passenger but in this book he meets a bigger, nastier evil which gets its own PoV passages in a manner that indicates that the author expects us to take on that this is a real disembodied intelligence with the ability to possess otherwise innocent people. Dexter turns from being a psychotic vigilante to a supernatural investigator and ends up taking on a god in a climax that really doesn't fit well with the rest of the series to date.