In 1984, Sir Kenneth Newman updated Sir Robert Peel's analysis by listing the following five functions of the police: (1) the upholding of the rule of law, (2) protection of and assistance to the citizen, (3) cooperation with others, (4) maintenance of a peaceful community, and (5) freedom from fear of crime. These five functions are performed through four basic systems: (1) detection and deterrent patrol and emergency response, (2) preventive and supportive local beat services, (3) crime investigation, and (4) management and operational support. The population served by the 24-hour patrol section includes active criminals; vehicle drivers; and moving populations of workers, tourists, and shoppers. These police also serve systems like intrusion alarms and respond to crises. Local beat services focus on senior citizens, single women, crime victims, families, ethnic groups, resident active criminals, and schoolchildren. The investigative section provides investigators on referrals from the patrol and beat sections. The management and operational support section is designed to relieve the other three from tasks that diminish their respective functional operations and to support them when they are at risk of becoming dysfunctional due to heavy demand. An interactive stochastic simulation model similar to the one developed for the National Health Service is a useful way of showing the relationships among the different functions and sections. Figures and 5 footnotes.