Psychological research into the role of bystanders in crime situations, both at the empirical and scientific level, presents practical difficulties, which account for the scarcity of data in this area. Methodologies of recent studies focused on two approaches to the bystander's role: as a catalyst in the commission of a violent crime, chiefly murder or as good Samaritans, either in staged or in real-life situations. Instances of heroic interventions to prevent the commission of an act of violence, or to chase the culprits in a robbery, often resulted in fatal injuries to the Good Samaritan-bystanders. The element of personal danger is, of course, the main cause of the reluctance of most citizens to get involved in a crime situation. However, even when personal danger is not a consideration, the majority of citizens do not cooperate with the police and refuse to get involved because of the complexities and inconveniences to the witness in a criminal court case. So far, such inconveniences have not been alleviated by any actual or contemplated measure by the criminal justice system. Problems faced by the witness in the courtroom include stressful questionings and cross-examinations; threats by the accused, his family and friends, loss of working time; and even the possibility of detention as a material witness. The community at large offers the best solution to the problem of crime prevention. Block associations (despite the dangers of vigilantism) have proved effective in making neighborhoods more safe, as well as serving as catalysts for further positive social interaction. Citywide programs involving citizens with similar occupations, urban planning, and environmental design, are further examples of successful citizen involvement. Fifty-nine notes are given.