To date, researchers interested in the nature, extent, and correlates of delinquent behavior have relied exclusively on official--police, court, and prison records--and self-report data. The availability of the NCS data on personal and commercial victimization presents an opportunity to use a third data source that avoids many of the problems and limitations inherent in official and self-report data. This research uses such data to analyze the involvement of juveniles (under 18 years old) in offenses where victims come face-to-face with offenders (rape, personal and commercial robbery, assault, and personal larceny). For comparative purposes, the criminal involvements of juvenile offenders were compared with those of youthful offenders (18 to 20 years old) and adult offenders (21 years or older). Throughout the research, emphasis is given to the extent to which these victimization results are compatible with results from studies of official and self-reported delinquencies in the areas of the characteristics of juvenile offenders and the nature of their illegal activities. The format of this final report is divided into summaries of five larger separate reports that deal with (1) trends and patterns of juvenile criminal behavior in the United States; (2) an analysis of rates of juvenile criminal behavior and victim characteristics; (3) juvenile criminal behavior in urban, suburban, and rural areas; (4) juvenile criminal behavior and its relation to economic conditions; and (5) juvenile criminal behavior and its relation to neighborhood characteristics. The findings of each report are listed, along with five references.