This book follows the adventures of Dave Valentine as he becomes a wolf (a scout for a freedom fighting group) in a post apocolyptic world where vampires rule. The vampires in question are actually alien beings that feed off of life aura. They have not only infected our planet but through a use of a star gate like technology have invaded the universe. There are some non evil Kurians that didn't go down the vampiric road that helps hummanity by awaking humanities more savage nature.
This is the first novel in the Vampire Earth series and as so it is more concerned with world building and really only develops Valentine as a character. It intentionally mixes science fiction and fantasy, giving fantasy aspects with science fiction explanations. An example are the grogs. They are your basic orc but Knight has them genetically created.
It was a pretty good book and makes me want to read the others in the series. This one isn't for the kiddies as the end of the book has to do with rape and prostitution. Fantasy and Science Fiction fans should enjoy it. Not sure about twilight fans as the vampires are not romanticised at all.