After an overview of the relationship between drug use and crime, the authors examine the decline and revival of rehabilitation within corrections, followed by an examination of the two main prison-based substance-abuse treatment modalities, i.e., therapeutic communities and cognitive-behavioral programs. In reviewing the history of corrections-based substance-abuse treatment programs in California, the article reports that early State efforts to address "narcotics addiction" began with the Civil Addict Program, which was begun in 1961 at the California Rehabilitation Center. As with many correctional programs, this program, along with other prison-based programs, was greatly weakened, if not eliminated, during the "nothing works" backlash of the 1970's and 1980's. With the revival of a rehabilitation focus in the 1990's, however, California again became a leader in providing treatment to substance-abusing offenders. The Office of Substance Abuse Programs (OSAP) was established to guide the design and implementation of new treatment programs. The selected treatment model was the therapeutic community (TC), modified for the prison environment. This involves housing treatment participants in a unit separate from the general inmate population for a treatment regimen that lasts for 9 to 12 months. To reinforce the gains of in-prison treatment, community treatment follows release to parole. After brief descriptions of particular California in-prison treatment programs, the authors offer suggestions for improving correctional substance-abuse treatment. In the area of the treatment process, they advise that examining issues of the treatment process remains a critical task in improving treatment delivery within correctional settings. Organizational and systems characteristics and the dynamics of criminal justice treatment require further study to create more effective systems of care and supervision for offenders. Regarding continuity of care, the authors note that research on aftercare to date has several methodological weaknesses, including lack of unbiased assignment to aftercare conditions; confounding of the separate effects of treatment duration and aftercare and their interactions; and the lack of a TC aftercare condition for parolees who have not had prior in-prison TC treatment. The authors also comment on the need to improve the integration of the correctional system and the treatment system, as well as the interaction of evaluation, policy, and programming. 105 references