Family influences on juvenile crime are identified, including weakened family education, family disruption, lack of parental control and supervision, and parental criminality. Comparisons of delinquent and nondelinquent populations reveal differences in morals, attitudes, values, interests, and recreations. Other factors identified with juvenile delinquency include poor school experiences, negative influence of delinquent peers, improper socialization, joblessness, and the turmoil associated with the cultural revolution and subsequent changes in Chinese economic and social policies. Personality characteristics of delinquents are profiled, and psychological characteristics of adolescence that may contribute to delinquency are identified, including striving for independence, incomplete cognitive development, impulsiveness, and self-interest. Policies for preventing delinquency are recommended, and the excellent track record of work-study schools in reeducating and rehabilitating juvenile delinquents is discussed. Finally, definitions, behavior patterns, and trends in juvenile gang activity are examined, and recommendations are made for a criminal justice response to it. Tables. For separate articles, see NCJ 111591-111598.