The research used multistage cluster samples of high school students in each city, together with a purposive sample of high school dropouts. The samples included 200 students and 50 dropouts in each neighborhood. The youths ranged from 13 to 20 years old, included both males and females, and were mainly black and Hispanic. The youths completed surveys in the spring and fall of 1985 providing information on demographic characteristics, delinquency, drug use and sales, victimization, and topics indicating social learning and control. Findings showed that both gang and nongang youths are involved in serious delinquency and drug use, although fewer nongang youths appear to be involved in these behaviors. In addition, gang members and gangs vary widely in their delinquency. Research recommendations, tables, glossary, and notes.