The research followed the 13,160 males and 14,000 females through age 26. The sample had a well-balanced distribution of participants by race, gender, and social class. The analysis focused on offense patterns and seriousness, juvenile court dispositions, and offender characteristics. Results revealed 71 percent of the participants remained free of both official delinquency and adult crime through age 26. A total of 15.6 percent had an official record of delinquency but did not go on to adult crime, 7.5 percent committed criminal acts during both time frames, and 5.8 percent committed crimes only as adults. Cohort members were most likely to continue as adults as they had behaved as juveniles. In addition, delinquents who continued their criminality as adults differed significantly from those who began criminal careers as adults only. Moreover, starting a delinquency career early, continuing this career through adolescence, and being active just as the juvenile period ends at age 17 were important predictors of adult criminality. However, those whose delinquency began late were also at high risk of adult criminality of only a very short time remained in which they could discontinue their delinquency career. Discussion of implications for theory and policy, tables, name and subject indexes, and approximately 250 references