Twenty years after his famous memoir, the man who literally wrote the book on FBI criminal profiling opens his case files once again. In this riveting work of true crime, he spotlights four of the most diabolical criminals he’s confronted, interviewed and learned from. Going deep into each man’s life and crimes, he outlines the factors that led them to murder and how he used his interrogation skills to expose their means, motives, and true evil. Like the hit Netflix show, is centered around Douglas’ unique interrogation and profiling process. With his longtime collaborator Mark Olshaker, Douglas recounts the chilling encounters with these four killers as he experienced them—revealing for the first time his profile methods in detail. Going step by step through his interviews, Douglas explains how he connects each killer’s crimes to the specific conversation, and contrasts these encounters with those of other deadly criminals to show what he learns from each one. In the process, he returns to other famous cases, killers and interviews that have shaped his career, describing how the knowledge he gained from those exchanges helped prepare him for these. A glimpse into the mind of a man who has pierced the heart of human darkness, unlocks the ultimate mystery of depravity and the techniques and approaches that have countered evil in the name of justice.