In the Netherlands, victim surveys show that petty crimes account for about 50 percent of offenses, while over 90 percent of reported crimes are classified as petty offenses. Experiments in Amsterdam, Hoogeveen, and The Hague have demonstrated that different and more frequent types of patrol combined with crime prevention information have decreased certain offenses, especially vandalism, and improved people's feelings about crime and their willingness to call for police assistance. In the crime detection area, an experimental burglary project by the Utrecht Municipal Police used a team of detectives and patrol officers who were given a special information system, and the numbers and percentages of cases solved increased. More difficult cases were solved in proportionately less time. These findings indicate that prevention schemes must be selected more carefully, since some types of offenses are much more susceptible to deployment of additional manpower than others. The type of patrol is important in those crimes which respond to patrol. Frequent visible patrols on foot or bicycle are more successful than police cars driving around randomly. More police manpower is necessary, but some increases could be achieved by redeploying the existing police force. Selective investigations should concentrate on cases with the best chances of being solved and use the latest management techniques and computerized data processing systems. Tables and six footnotes are included.