The success or failure of drug treatment programs have long been evaluated by assessing the clients’ progress while in treatment and their status upon completion. This approach does not provide a complete assessment or an adequate picture of treatment outcomes over time. A comprehensive evaluation of the success or failure of treatment should also include client status in the years following treatment for a fair assessment of the long-term efficacy of any drug-treatment program. What happens to former clients who left treatment? What influence did the treatment have on their lives? These are the questions that Marvin R. Burt seeks to answer with the follow-up studies included in this book. By selecting samples of former clients treated by two of the largest drug treatment agencies in the U.S. and control groups, Burt compares client behavior in terms of drug abuse, criminal activity, and socioeconomic productivity before, immediately following, and well after treatment. The findings in this book challenge many common assumptions about drug treatment programs. Burt finds larger than expected positive behavioral changes in clients regardless of treatment duration or type, and demographic or background characteristics. Whether the results are attributable to the clients’ maturation, commitment to change, or a reduction in the availability of drugs, the positive results of treatment are encouraging. This volume provides valuable insight into the natural history of drug abuse and outcomes for client groups.