A series of interviews obtained retrospective information on the inmates' criminal careers. To encourage confidence and open discussion between the inmates and the researcher, the researcher spent considerable time interacting with the inmates in prison. Inconsistencies were identified by reinterviewing the inmates in groups of five, by careful analysis of the interview material, and by conducting additional interviews with individual inmates and staff. The interviews focused on "episodes" that included the first offense, life on the margins of prison, the initial prison experience, and the point at which continued imprisonment became an accepted part of the offender's lifestyle. The study found that offenders chose a criminal identity based on decisions that appeared rational to them. Several "rules of behavior" were identified. A charting of the changing relationships of the offenders showed that the juvenile justice system contributed to the forging of a criminal identity as the offender incorporated into his lifestyle the State's reaction to his delinquency. The study also revealed how the young offender's identity became incongruous with his behavior and how what the offender said often differed from what he believed and how he behaved. 15 tables, 190-item bibliography, subject index.