The first police departments were created in the United States because of the need to control mob violence which was common during the 19th century. Police officers were viewed as being dominated by political bosses who controlled their hiring practices and policies. Reform movements in the 1920's culminated in the concept of professionalism in the 1950's and 1960's. Police professionalism was interpreted to mean tough, rule-oriented police work featuring advanced technology and hardware. However, the view that these measures would quickly reduce crime proved incorrect. At the present time, there are several major law enforcement agencies, including the Federal Bureau of Investigation, the Drug Enforcement Administration, the U.S. Marshals Service, and the Secret Service. County-level law enforcement is provided by sheriff's departments, and most States maintain State police agencies. Most law enforcement activities, however, are carried out by local police agencies. The police role is multi-level in that police officers fight and investigate crime, keep the peace, and provide community services. Police departments faced several crucial issues, and one involves understanding the police personality and its effect on performance. Other issues include police discretion, women and minority police officers, police violence, and technology. 197 notes, 5 figures, and 6 photographs