Data were collected from a stratified random sample of 553 urban adolescent males from 12 New York City neighborhoods. Separate, simultaneous interviews were conducted with each adolescent and his mother or female guardian. The interview with the adolescent covered behavior and attitudes toward parents, peers, and school as well as a wide range of self-reported delinquent behavior. The mother's interview addressed neighborhood-relevant information, familial social characteristics, marital relations, parent-child relations, parental antisocial behavior, mother's mental health, and mother's report of her child's behaviors. Measures of neighborhood characteristics were derived from census data and information reported in the interviews. The data indicate the importance of considering distinct community contextual effects in addition to individual-level effects as delinquency factors. Two neighborhood-level factors were particularly significant in explaining delinquency: the community's level of organizational participation and the extent of disorder and criminal subculture. 3 figures, 3 tables, 63 references. (Author abstract modified)