This is an old paradigm in drug-user research, one that has produced some of the richest descriptions in the literature. It draws on the analytic approach developed to study other criminal activity in terms of "criminal careers" as well as the literature that describes the variety of career "patterns" for substance users. Research into drug-user careers focuses on the most serious, chronic substance users and examines the predictors of transition from lower level involvement to higher levels of involvement. Their use differs from that of experimental or social-recreational use in terms of its frequency and its significance in the user's life. The bibliography is divided into two general headings: research that describes drug-use careers and methodological issues in studying drug-use careers. It ranges from classic narratives of the lives of drug users to discussions of the problems of trying to characterize accurately or to follow complex lives over time. 83-item bibliography