It has come to be believed that preventative patrol is an essential element of effective policing. in the face of spiraling crime rates, the most common answer urged by public officials and citizens alike has been to increase patrol forces and get more police officers “on the street.” The assumption is that increased displays of police presence are vitally necessary in the face of increased criminal activity. Challenges to preconceptions about the value of preventive police patrol were exceedingly rare until recent years. Beginning in 1962, however, challenges to commonly held ideas about patrol began to proliferate. As reported crime began to increase dramatically, as awareness of unreported crime became more common, and as spending for police activities grew substantially, criminologists and others began questioning the relationship between patrol and crime. The Kansas City (MO) PD, under a grant from the National Policing Institute, conducted a comprehensive experiment to analyze the effectiveness of routine police patrol. It involved variations in the level of routine preventive patrol within 15 Kansas City police beats. These beats were randomly divided into three groups: reactive, control, and proactive. The experiment found that the three experimental patrol conditions appeared not to affect crime, service delivery and citizen feelings of security in ways the public and the police often assume they do. Some of these findings pose a direct challenge to traditionally held beliefs. Some point only to an acute need for further research. But many point to what those in the police field have long suspected—an extensive disparity between what we want the police to do, what we often believe they do, and what they can and should do.