Research is increasingly demonstrating the effectiveness of treatment for incarcerated populations in reducing recidivism and drug use, especially treatment in a therapeutic community (TC). Transitional services that include TC treatment in a work release setting greatly reduce recidivism and relapse, as do aftercare services. Although treatment options in prisons are increasing, there are many more who could benefit from treatment than receive it. The article describes treatment within the Delaware criminal justice system that supports the efficacy of TCs and makes a strong case for continuing treatment services as the offender rejoins the community. The article recommends research on: (1) what types of treatment programs are best suited for what types of offenders and at what stage of criminal justice processing; (2) how well diversion programs are working and how to identify which ones work best; (3) whether TCs are the ideal programs for prisons; (4) the efficacy of 12-step programs, alone or as an adjunct therapy; (5) the efficacy of transitional and aftercare treatment services in the community; (6) compulsory versus voluntary treatment; and (7) other alternatives for addressing the needs of drug-involved offenders, including drug courts. Figures, references