Until recently, crime prevention was neglected because its results are unquantifiable and because of police legal constraints that protect citizens' rights against excessive state control. Preventive police work is a new field with little precedent, tradition, or credibility. Implementation of police crime prevention programs is also hampered by personnel resistance, lack of training, and resource inadequacies. The enormity of the known crime rate, and material losses from crime, however, make a concerted preventive effort mandatory. Among specific prevention measures to be pursued are wide-ranging media and public information campaigns including police information booths in public places and specialized liaison officers for public and juvenile relations. Coordinated city planning should provide physical deterrents such as better street lighting, electronic scanners in high-crime locations, and architectural designs for defensible space. Targeted patrols should be assigned to surveillance of public transportation networks, and other specialized police units should be developed. Citizens should receive counseling on home and personal security as well as general crime awareness. Groups in need of special preventive guidance are juveniles and foreigners. Planned preventive policing should also take place in anticipation of mass gatherings, sports events, and demonstrations. The number of recent police training seminars and publications on prevention indicate the growing acceptance of this direction in criminal policy. Footnotes are supplied.