It offers a general definition of violence and examines the most serious forms of individual or small group violence not authorized by the state -- homicide, aggravated assaults, and robbery -- as well as the various forms of state-authorized or countenanced collective violence, ranging from torture, genocide, vigilantism, riots, and labor strikes to terrorism. On the basis of literature reviews, policy recommendations are formulated for each form of violence. Notable is the relative stability or, at most, modest inclines of the homicide rates. Robbery and assault rates are higher in developing than in developed countries. Robbery clearly appears as part and parcel of national development, but assault exhibits no such pattern. Constitutions in 55 nations explicitly or implicitly outlaw torture, yet nations have done little to translate these declarations into action. Most of the information on genocide is in the form of polemical descriptions. Additional data needs to be collected. Features of collective violence which tend to distinguish it from other forms of violence are that it is a collective act, it can be directed at property, and it is intended to serve some long-term objective beyond that of individual gain. It is recommended that the United Nations Section on Crime Prevention and Criminal Justice initiate an effort to increase its capability to coordinate and administer a research-based prevention and control policy in concert with member countries. This report includes 149 references.