Major theories of delinquency causation include biological and genetic theories, psychodynamic theories, the social learning theory, social control theory, limited opportunity theory, and subculture theory. No single theory provides an adequate explanation, however, indicating that no single causative factor exists. Nevertheless, empirical research has shown numerous factors to be correlated with delinquency, including sex, cognitive and intellectual factors, and environmental factors such as child abuse, school experiences, and mobility. School experiences have been consistently found to be important in the development of delinquency. Classification schemes and typologies have identified a variety of homogeneous subgroups of delinquents. Evaluations of treatment programs have generally yielded inconsistent and discouraging results, but no evidence exists that incarceration is the most effective way to deal with delinquency. However, treatment efforts must recognize and incorporate the heterogeneity of delinquents. Some early intervention programs emphasizing parent training or developing problemsolving skills in young children are showing promise. 118 references.