The catchment area of the Afan Alternative Project was the Petty Sessional Division of Afan in West Glamorgan, served by the Port Talbot Magistrates' Court. The intent of the project was to provide intensive group work for probationers. The intention of the group work was to examine attitudes, feelings, behavior, and the situations in which group members committed offenses. Data relevant to the project's effectiveness were obtained over the period 1980-85. Sentencing data indicate the project was successful in reducing custodial sentencing for the target group. Those participating in the program would have been at high risk of incarceration without the program. There was no evidence of 'net-widening' nor of the erosion of the use of other noncustodial sentencing options. Indirect evidence from the self-report study suggests that the majority of the project's clients experienced a reduction in the range and intensity of life difficulties. There is some evidence of a reduction in recidivism rates below expected levels, particularly in the second year of participation. Program costs were much less than incarceration costs but higher than regular probation costs. The study identifies factors that increased and reduced project effectiveness and considers its replicability. 43 tables, 2 figures, chapter notes, 115-item bibliography.