Serious crime is declining in many big cities across America. Meanwhile, the country's largest and most violent cohort of young males will soon reach its crime-prone years. Smarter law enforcement and tougher sentencing policies explain much of the recent drop in crime and can minimize the damage from the next crime wave. Many criminologists, however, are unwilling to admit that law enforcement can decrease crime. Part of the answer is that more than a dozen major empirical studies over the last two decades have failed to show either that police personnel resources and crime rates vary inversely or that particular types of community-oriented policing practices prevent crime. Academic experts who view such negative findings as the last word on the subject are mistaken. Following an exhaustive review of the empirical literature on policing, David H. Bayley recently concluded that there has never been "a rigorous, clear-cut test of the association between the visible presence of the police and crime rates." Bayley is now in the early stages of a quasi- experimental study designed to test this relationship while controlling for demographic and other variables related to the incidence of crime. Such fine-tuned research on patrol presence, policing strategies, crime rates, and other key variables has become possible only in the past few years with the development of computer-assisted information systems for police dispatching and management. There is significant empirical support for another proposition that many criminologists reject: sentencing policies that keep violent and repeat criminals behind bars contribute to reductions in crime. As the next crime wave draws near, there must be a concerted effort to target hardened adult and juvenile criminals for arrest, prosecution, and incarceration. Any effective anti-crime policy must advance one or more of three interlocking anti-crime strategies: hardening targets, targeting the hardened, and targeting resources.