Besides from official records, study data were collected in interviews with social services authorities and with members of three relatively long-lived gangs. Data were also collected on 279 of the subjects' comrades in crime. Findings show that juvenile crime is often a social activity committed as a means to social acceptance; nearly half of the children monitored were acquainted with at least one other juvenile in the study. In the large networks identified, the most criminally active juveniles moved around a lot and had links to many of the other juveniles in the study. They were popular and had a central position in their gang. Most of the gangs did not have crime as their dominant activity, offenses were committed spontaneously, and most members had temporary gang memberships and short criminal careers. The more criminally experienced gang members would often teach younger and less experienced members criminal skills. Juveniles usually became gang members at around age 14 to 16, their criminality peaking after a short time and then receding. The longer the delinquent period lasted, the less likely the juvenile was to return to a socially acceptable life. If the delinquency continued, the youth's circle of delinquent friends was likely to expand from the neighborhood, to his area of town, to even larger regions. Additional findings, the study data and survey instrument, and 66 references are provided.