In 1987 Delaware established the Key, a prison-based treatment program for drug-involved offenders at a men's maximum-security prison. The Key is a therapeutic community, a self-contained treatment environment separated from the rest of the prison. The treatment model is based on the philosophy that drug abuse is a disorder of the whole person and that treatment should focus on building an offender's self-esteem and changing his values and attitudes. A post-release program was established at the Crest Outreach Center, a conventional work-release center. After release from the Key program, offenders enter the Crest Center for 6 months of treatment and job training in a therapeutic community setting. In 1992 researchers began conducting follow-up interviews with participants at 6 and 18 months after completion of the Key program. They also conducted urine and blood tests to check for drug use and exposure to HIV. The follow-up interviews involved four groups of offenders: a comparison group, which received no treatment; a Key group, which received only prison-based treatment; a Crest group, which received only treatment at the work-release center; and a Key-Crest group, which received treatment in both the Key and Crest programs. Findings show that at 18 months after release, drug offenders who received 12-15 months of treatment in prison followed by an additional 6 months of drug treatment and job training were more than twice as likely to be drug-free than offenders who received prison-based treatment alone. Offenders who received both forms of treatment were also more likely than offenders who received only prison-based treatment to be arrest- free 18 months after their release (71 percent compared to 48 percent). 1 table