This book is intended to advance criminological knowledge by reporting empirical studies on the nature and progress of criminal and delinquent careers, prospective, longitudinal studies of the etiology of crime and delinquency, and interdisciplinary research intended to provide an integrated understanding of delinquent and criminal behavior. Three longitudinal studies of criminal and delinquent careers (1) compare the criminality of one cohort with a later cohort to examine differences in crime patterns, (2) examine delinquent and criminal careers of a cohort of British youths, and (3) explore the criminal careers of violent offenders in Denmark. Other longitudinal studies identify antecedents of crime and delinquency. Most of the studies measure family structure, stability, and conflict and test them as antecedents of antisocial behavior. Interdisciplinary studies combine measurements from various disciplines to determine the influence of various factors on criminality, such as the combinations of IQ, aspirations, and expectations upon deviant behavior and the interaction of the biological factor of testosterone levels and situational factors to explain verbal and physical aggression. Chapter tabular data and references are provided along with a book subject index. For individual studies, see NCJ 91220-35.