The discussion notes the changing role of law enforcement and its evolution from simple functions involving little stress to complex and stressful endeavors requiring highly trained personnel. The first behavioral scientists in law enforcement were involved in psychological testing to aid the selection of police candidates. Their involvement expanded to including operational help in hostage negotiations, criminal personality profiling, domestic crisis intervention, crime scene analysis, and counseling police officers regarding personal problems inherent in police work. These early efforts seemed to come together in 1968 when the Los Angeles Police Department hired a full-time psychologist, thereby giving formal recognition of their important. Police psychology developed notably thereafter. The subsequent years have experienced a steady increase in the number of police agencies employing psychologists, the growing number of conferences where police psychologists share their successes and failures in the law enforcement setting, and the American Psychological Association's 1982 designation of a special section of an affiliate for psychologists who work in law enforcement. The history of these services reveals that among elements essential for their success are support at the management level and independence from the organization. Chapter reference notes, appended agenda of conference on police occupational stress, and 152 references