Over the last twenty years, critical discussion of Thomas Mann has highlighted the role of his homosexuality for his creative work. This not only is presented as a dynamic underlying Mann’s creative work, but also is the supposed reason for the theme of guilt and redemption that grew ever stronger in Mann’s fiction. Michael Maar mounts a devastating forensic challenge to this consensus: Mann was remarkably open about his sexual orientation, which he saw as no reason for guilt. But sexuality in Mann’s work is inextricably bound up with an eruption of violence. Maar pursues this trail through Mann’s writings and traces its origins back to Mann’s second visit to Italy, during which the Devil appeared to him in Palestrina. Something happened to the twenty-one-year-old Thomas Mann in Naples that marked him for life with a burdensome sense of guilt…but what exactly was it?