From the New York Times bestselling authors of Mindhunter comes their most riveting tale yet . . . The FBI's legendary pioneer of criminal profiling and inspiration behind the hit Netflix show Mindhunter , John Douglas has spent decades working with law enforcement to understand the criminal mind and hunt violent predators. Now Douglas, along with his longtime collaborator Mark Olshaker, turns his keen eye to four of the most disturbing killers he has confronted. Offering never-before-revealed details about his interview techniques and profiling process, Douglas goes step by step through his encounters with these murderers, connecting each sadistic predator's crimes to his conversation with them. In doing so, he shows his unprecedented ability to get into the heads of both predator and prey as he talks to the country's most dangerous men, and how he used his interrogation skills to expose their true evil.