#1 New York Times–bestselling author of The Magicians: A "fabulously entertaining" novel of a medieval manuscript, a modern video game, and a man obsessed (The Boston Globe).

About to depart on his first vacation in years, Edward Wozny, a hotshot young investment banker, is sent to help one of his firm's most important and mysterious clients. When he's asked to uncrate and organize a personal library of rare books, Edward's indignation turns to intrigue as he realizes that there may be a unique medieval codex hidden among the volumes, a treasure kept locked away for many years and for many reasons.

Meanwhile, as friends draw Edward into a peculiar and addictive computer game, his obsession deepens as he discovers surprising parallels between the game's virtual reality and the mystery of the codex. An accomplished and entertaining thriller, Codex explores the mysterious power of books in the medieval and modern ages.

"Captivating . . . [An] intelligent, enjoyable novel." —Publishers Weekly

"Takes its place on the shelf of self-referential, bibliophilic page turners like The Name of the Rose, Possession and A Case of Curiosities, and it's as entertaining as any of them." —The New York Times Book Review

"An exhilarating literary tour de force . . . mesmerizing from start to finish. A fabulous double-helix of a novel." —Baltimore Sun