What is ninth gate book?

The Ninth Gate is a gothic horror novel by Arturo Pérez-Reverte, published in 1996. The story follows Dean Corso, an unscrupulous rare book dealer who is hired to authenticate and acquire a satanic text known as "The Nine Gates of the Kingdom of Shadows." The book is said to contain the means by which the devil himself can be summoned and invoked.

As Corso travels from Europe to America and back, he finds himself caught up in a web of intrigue and mystery surrounding the book and its history. Along the way, he encounters several eccentric and dangerous characters, each with their own motivations for possessing the book.

The Ninth Gate was adapted into a film of the same name in 1999, directed by Roman Polanski and starring Johnny Depp. While the movie diverges from the book in some significant ways, it retains the themes of occultism, mystery, and betrayal that are central to Pérez-Reverte's work.