Fans of HellBlazer will recognise the name Mike Carey, as will fans of Lucifer, the ongoing series from Vertigo comics.
Carey's been writing in the comics world for quite some time now, recently carrying on some of the fae stories started in Neil Gaiman's Sandman as well as developing Lucifer and taking the reigns of writing Constantine stories.
This is his first novel, and whilst it has some of the flavour of a HellBlazer story there's enough there which is different to keep things fresh. The story involves a world very much like ours excepting the fact that ghosts not only exist, they are recognized by the government with all the legal issues that causes.
The main character, Felix Castor is a freelance exorcist who is hired to remove the presence of a Ghost from a London hall of records. Part of his method of exorcism is to learn about his subject, and in the course of doing so he realizes things are not quite what they seem.
Part mystery, part occult story this is an excellent read. Carey writes characters very well, as those who know his comic works will I'm sure agree. The story is by turns amusing, exciting and disturbing which makes for a very powerful read. Highly recommended.
Oh, and to correct one of the other entries Constantine is one of Alan Moore's creations, though Mike did a damn good job of writing an extended set of stories for the HellBlazer title.