I am now reading The Club Dumas, by Arturo Perez-Reverte. As I started to read it I realized it was the book on which The Ninth Gate, a movie by Roman Polanski starring Johnny Depp was based. The movie was only so-so, but the book is very good, very different. While investigating the authenticity of Dumas manuscript, a mercenary rare book dealer gets caught up in the mystery of The Nine Doors, a supposed manual for summoning the Devil. I have to limit myself to a chapter at a time otherwise I would have read the whole book in one day.
I'm probably coming late to the party here, the book was published in 1993 but I just saw it while wandering around the bookstore.