Analyses of longitudinal data show that socialization variables, such as lack of parental supervision, parental rejection, and parent-child involvement, are among the most powerful predictors of juvenile behavior problems and delinquency. Medium strength predictors include background variables such as parents' marital relations and parental criminality. Weaker predictors are lack of parental discipline, parental health, and parental absence. The effects of these factors seems to be about the same for both boys and girls. Analyses of concurrent studies comparing delinquents with nondelinquents and aggressive and nonaggressive children largely parallel these findings. Data from concurrent normal samples, however, show less importance for parental child socialization practices and relatively more importance for the child's rejection of the parent and the parent's rejection of the child. A small proportion of families produces a disproportionate number of delinquents. The presence of one child with delinquency, aggression, or covert conduct problems increases the probability that other children in the family will exhibit these behaviors. Deficiencies in parenting skills are associated with the seriousness of delinquency. Treatment studies show that systematic changes in parenting behaviors can lessen the frequency of a child's and siblings' conduct problems, and can, to a lesser extent reduce delinquent involvement. Approximately 320 references and 31 tables. (Author abstract modified)