Primary, secondary, and tertiary crime prevention efforts can target groups of offenders, specific situations, and victims. Secondary and tertiary crime prevention efforts have not been particularly successful. Situational crime prevention has four stages: analysis of the situational conditions, systematic study of possible means of blocking opportunities for specific crimes, implementation of the most promising and practicable measures in a way that permits evaluation, and dissemination of the results. Primary prevention through situational crime prevention includes measures such as target hardening, crime prevention through environmental design, and lighting. The biggest criticism of this approach is that it will simply displace the criminal act. This assumption denies the opportunistic nature of much crime, although a certain amount of displacement is likely, particularly in the case of a highly motivated career criminal. Overall, primary crime prevention efforts will probably increase into the 21st Century. Chart and 67 references