Spanish novelist Arturo Pérez-Reverte's 1993 action-adventure.
A rare-book mercenary named Lucas Corso takes on the task of authenticating a handwritten original draft of "The Anjou Wine", a chapter of Alexandre Dumas's The Three Musketeers. He piggybacks this favor onto his paying job -- searching out all the remaining copies of a banned 1666 manual on demonology and acquiring them for his client, a book dealer who must have them all. These lines of investigation do not stay separate for long.
He is accompanied at various times by an old colleague in the trade ("friend" is too strong a word), and by a young woman named Irene Adler who may be the devil. As the story progresses, Corso is plagued by antagonists who mirror characters from Musketeers, and he begins to suspect that he is living in some author's fiction.
The Club Dumas, set in a noir Europe, is written like a post-modern adventure serial, dense with cyphers and self-referentiality, yet viscerally as well as intellectually satifying. Pérez-Reverte's expert plotting and story arc effectively keep the reader on the hook with twists and cliffhangers that demand one continue to the next chapter. An excellent book that seamlessly weaves together mystery, action, and esotericism.