Main findings revealed that truant youth had significantly higher rates of illegal drug use, underage drinking, and smoking than their non-truant peers. Moreover, rates of substance misuse increased over time, with long-term truants reporting higher rates of all forms of substance misuse compared with other categories of truants. The association between truancy and illegal drug use and smoking remained strong after controlling for other possible explanatory factors, such as school experience, victimization, parenting, and various personality characteristics. The findings for school exclusion revealed that although students who had been excluded from school reported significantly higher rates of illegal drug use, underage drinking, and smoking than their non-excluded peers, the link between substance misuse and school exclusion was weaker than the link between truancy and substance misuse. The author contends that policies regarding truancy and school exclusion need to take into account the sex differences noted in rates of truancy and school exclusion. Specifically, girls make up the majority of truants by the second year of secondary education while boys form the majority of excluded students. The study was part of a larger study entitled, “Edinburgh Study of Youth Transitions and Crime” which involved the use of self-report questionnaires, semi-structured interviews, official records, teacher questionnaires, criminal records, parent surveys, and geographic information system to longitudinally investigate factors leading to involvement and desistance in delinquent offending among a cohort of 4,300 youth between the ages of 13 and 15 years. The study was conducted over a 2-year period and involved all 23 State secondary schools, 8 independent sector schools, and 9 special schools in Edinburgh. Methods and goals of this research are briefly summarized in this report. Figures, tables, footnotes, references