The data used provide information on situational aspects of police-suspect encounters, characteristics of the community and organizational contexts in which these encounters occur, and information on the officers involved. Four types of police agencies were identified by cross-classifying levels of bureaucratization and professionalism. Shallow bureaucracies that are also nonprofessional are labelled fraternal organizations, and nonbureaucratic, professional police agencies are called service agencies. Bureaucratic police departments characterized by low levels of professionalism are labelled militaristic, while bureaucratic, professional police agencies are called legalistic. Police in fraternal agencies base their arrest decisions on a number of considerations absent in the arrest decisions of officers in service agencies; e.g., police in fraternal agencies discriminate against female complainants compared to male complainants in tending not to make arrests. Moreover, police in fraternal agencies are more punitive toward suspects who commit minor violent offenses in predominantly nonwhite neighborhoods. The bureaucratic police agencies have greater indifference toward complainants in nonwhite areas and are also more punitive in lower status neighborhoods. One consequence of increasing burearucratization and professionalism of police agencies is a tendency for officers to exercise more legal control in their encounters with youthful offenders. Police in such agencies are also more likely to make arrests in interpersonal disputes. About 190 references are provided.