As an innovator at the FBI in the late 1970s, John Douglas developed new techniques for hunting serial killers and sex offenders. Advancing the use in investigations of the procedure known as criminal profiling, Douglas became widely recognized as its top authority. A mix of psychology, pattern recognition, and inductive reasoning, criminal profiling allows investigators to make educated guesses about suspects--sometimes accurately predicting their age, background, personality, and other identifying characteristics from the barest of clues. While leading the FBI's Investigate Support Unit, Douglas used profiling with success in several prominent cases.

An Air Force veteran with a doctorate in education, Douglas began as an FBI special agent in Detroit in the early 1970s. Assigned to bank robberies, he spent time talking with robbers about their craft. By 1977, convinced that investigators needed to understand the criminal mind better, he joined the FBI's Behavioral Science Unit at Quantico, Va...