In the spatial analysis, data relating to the residence of juvenile offenders were mapped for the years 1966, 1967, 1971, and 1977. High rates over the full range of offender indices were found with the greatest consistency in the inner-city terrace areas of Butetown, Grangetown, Adamstown, and Splott; this suggests that in these parts of Cardiff, the term 'delinquency areas' could be used. In the ecological analysis, the characteristics of a 1966 delinquency data set derived from the South Wales Constabulary were examined, and the relationship between juvenile delinquency indices and aspects of the physical, demographic, and socioeconomic environment was analyzed. The study found that the relationship between these indices and socioeconomic status was the strongest and most persistent. The behavioral analysis involved the evaluation of survey response data collected in a questionnaire sent to households in two low social status areas of the city. Three main theoretical approaches to the explanation of juvenile delinquency were addressed in the questionnaire. The approaches related to (1) social disorganization, anomie, and cultural conflict as delinquency factors; (2) subculture theory as an explanation of delinquency; and (3) differential opportunity and status frustration as delinquency causes. The analysis provided strong support for the hypothesis derived from the subcultural approach. Significant differences were found between the delinquent and nondelinquent survey areas in terms of attitudes toward delinquent acts; in the actual behavior of children as opposed to parental attitudes toward certain aspects of child behavior; and in modes of child punishment. Further research is needed to determine why differences of attitude and aspiration between delinquent and nondelinquent areas exist and to further explore areas in which crimes are committed. Notes are provided for each chapter. A total of 2 figures, 32 maps, 36 tables, and a bibliography of about 100 citations are included. The questionnaire schedule is appended.