In examining the effectiveness of prison-based cognitive-skills programs in reducing reoffending after release, this chapter focuses on three evaluations: Friendship et al., 2002; Falshaw et al., 2003; and Cann et al., 2003. Regarding probation-based cognitive behavioral programs, researchers have been working for nearly 4 years on the study and evaluation of the cognitive program called "Think First." This chapter describes the primary objectives of the prospective evaluation and reports on attrition and the poor overall attendance rates for the programs. The major effects of poor attendance were low completion rates, early attrition, and the termination of one in five programs. The characteristics of probationers with low attendance and completion rates are outlined. Program completers who were assessed as medium-risk and high-risk had significantly lower reoffending rates than noncompleters in these risk categories. All the evaluation studies show the need for well-designed and rigorously executed evaluation studies and the importance of improving knowledge about the types of offenders who are most likely to benefit from specific programs. For the majority of offenders who began the prison and probation programs, the expected outcomes in reduced reoffending were not achieved. These evaluations are a beginning in the journey toward developing multiple programs whose sequence, timing, and coordination can meet the many and diverse need of probationers and inmates. 6 tables, 8 figures, and 22 references