This social history extends from 18th century London to 20th century California and explains why police forces have developed differently in the major cities of America. Police personality profiles highlight the book. The three major models of policing in Great Britain from 1748-1890 are examined. The manner in which police forces of the period coped with problems of vice, crime, and social unrest are outlined. Police methods and attitudes are discussed for New York City from 1845-1914; for Boston from 1854-1943; for the states of Pennsylvania and New Jersey from 1905-1940; and for the state of California from 1901-1942. When a law enforcement comparison was made of American and British cities, it was found that levels of safety and law and order have always been higher in Britain. Two of the broadest problems that faced the American police were vice crimes and gangs of predatory males. On a higher level, the gangs became organized racketeers and professional criminals. The American police have been more concerned with antisubversive activities over the years. Models of law enforcement are illustrated, including the patrol type, the constabulary, and the detective model. The three mechanisms for control of the police -- law, administration, and politics -- are detailed. The practical differences among the three mechanisms are discussed. In dealing with group images, the existence of five major interest groups are noted: the social elite, the business elite, the progressive, the blue-collar class, and the radicals. The effects of these groups on police development are outlined. A discussion of the secret agents of the Federal Bureau of Investigation and the Secret Service from 1850-1945 is presented. Photographs, a bibliography, and extensive notes are provided.