The author developed and directed a crime prevention program in the upper West Side of Manhattan starting in 1953 and came into frequent contact with neighborhood youths over the next 4 years. Data were gathered by means of interviews, questionnaires, agency conferences, and discussions with police and other officials. Many of the interviews with gang members were tape recorded. The analysis focused on two gangs: the Egyptian Kings and the Balkans. The analysis concludes that violent gangs are a recurrent social phenomenon in many places and are related to deep problems in society. Therefore, efforts to address gangs must distinguish between broad social change and the practical tactics of local control. The use of detached gang workers to reach gangs in their own communities is a significant approach to violent gangs. However, detached workers need training to diagnose accurately several types of gang structure. Marginal members require different treatment approaches from those needed for core gang members and leaders. Detached gang workers should avoid giving the leader credence that will reinforce the violent gang structure and must avoid sanctioning or taking part in deviance to gain what will turn out to be a false acceptance and rapport. Instead, detached gang workers should serve as law-abiding adult role models. Their goals should be do dismember the gang rather than redirect its activities. Adult-youth associations can be a useful way to reach marginal gang members; recreation is an effective approach for these associations. Group therapy can also be extremely useful. Additional recommendations, footnotes, and case examples