Based on its findings, the study concluded that being nervous and withdrawn protected boys against offending in adolescence, but that these protective effects tended to wane after age 21. The study found that the best predictors of late-onset offending compared with early-onset offending included nervousness, having few friends at ages 8-10, and not having sexual intercourse by age 18. The best predictors of late onset offending compared with nonoffending included teacher-rated anxiousness at ages 12-14 and high neuroticism at age 16. The study suggests that personality and behavioral factors evident in childhood indicate high risk for offending as young adults, such that early intervention might prevent a variety of maladjustment problems and behavioral difficulties as adults. The Cambridge Study in Delinquent Development was used to examine early determinants of criminal behavior. A sample of inner-city London males (n=400) were monitored from ages 8-10 to 48-50. Thirty-five of the participants were late-onset offenders who were first convicted of an offense at age 21 or older, and they did not have high self-reported delinquency at ages 10-14 and 15-18; 129 early-onset offenders were first convicted of an offense between ages 10 and 20; and 236 of the participants had never been convicted of an offense. A wide range of childhood, adolescent, and early adulthood risk factors were measured from self-reports and data provided by parents, teachers, peers, psychologists, social workers, and psychiatrists. 7 tables and 82 references