This volume describes the findings of a longitudinal, birth cohort study of juvenile delinquency in Puerto Rico. Carried out under the auspices of the Puerto Rican Senate's Special Crime Commission, the book represents a new type of birth cohort study, based on the classic work done in Philadelphia. The authors have traced Puerto Rican children born in 1970, both male and female, through the greater San Juan police departments, charting the incidence of delinquency and the number of recurring offenders. These findings are compared to the Philadelphia studies of 1945 and 1958. The book begins its examination with a discussion of the background for the current study. Literature on juvenile delinquency in Puerto Rico is reviewed, official statistics are cited, and a discussion of the birth cohort and the importance of longitudinal studies is provided. Chapter 2 addresses the prevalence of delinquency, and chapter 3 details its incidence, severity, and types of offenses. Succeeding chapters cover such areas as age and delinquency, delinquent recidivism, and police and court dispositions. The volume concludes with a section on cohort comparisons, a summary of the findings, and some policy implications and suggestions for legislation. A group of appendices is also included. This work will be an important addition for courses in criminology and sociology, as well as a valuable resource for college and university libraries.