This book is the first of the Harry Dresden books by Jim Butcher.
This is the second time I've read them, and they're quite good. I've started reading the books from scratch again in anticpation of the new one, Turn Coat, that has already come out. The basic book is about a private Wizard for Hire, Harry Dresden that does private supernatural consulting for the police to pay the bills, and private cases in his spare time. These two lines of work collide, as a crazed magician begins using forces beyond their control to wreak havok on Harry and everyone else in his life. He has to confront the Mafia, Vampires and even his own side in the form of a vengful 'Gaston' like character called Morgan.
The books are an astoningly fast read, especially given the sophistication of the setting and the plot. Inside of the action packed pace he manages to cram significant character development and introspective drama. The pacing is almost perfect, and you can see why it became as successful as it is.
Having seen that, you can also see Butcher's progression as a writer as the plot is a slight bit formulaic (albiet only for about four books) and Harry is a touch bit more charismatic with the ladies than one might expect. But that all quickly gets flushed out and rectified in the later books. I highly recommend it, but then again I would if I was bothering to read it a second time.