A New York Times and Sunday Times bestseller. When historian Diana Bishop opens an alchemical manuscript in the Bodleian Library, it's an unwelcome intrusion of magic into her life. Now Diana exposed herself to a world she's kept at bay for years; one of powerful witches, creative, destructive daemons and long-lived vampires. Sensing the significance of Diana's discovery, the creatures gather in Oxford, among them Matthew Clairmont, a vampire geneticist. Diana is inexplicably drawn to Matthew and, in a shadowy world of half-truths and old enmities, ties herself to him without fully understanding the ancient line they are crossing.