La Nona Porta

Dean Corso, based in New York City, is a rare book consultant and broker, and like many in his business is unscrupulous in bilking unsuspecting people for his own monetary benefit. One of his standing clients, publisher and academic Boris Balkan, whose rare book collection focuses solely on the Devil, has just acquired what he considers the crowning glory of his collection. It is a purported original of the seventeenth century "The Nine Gates of the Kingdom of Shadows" by Aristide Torchia. Balkan's copy is one of only three known in existence, the other two, also in private hands, in Portugal and France. Balkan believes only one of the three is authentic, he giving Corso the lucrative assignment of traveling to Europe to determine which of the three is the authentic one, and if it isn't his to acquire that copy. Corso will find that this assignment is a dangerous one as people associated with any of the three copies end up dead, their demises seemingly tied to the contents of the books themselves. Added to the mix is a young woman who seems to know as much if not more about the books and their current owners than him.