In reconstructing the emergence of critical perspectives on decarceration, the author examines analytical and empirical problems in the research that has claimed to find no significant constructive value in community programs and other alternatives to prison. Analytical and empirical problems in the research are identified. One analytical bias has been the tendency to reject alternatives to prison as little more than "widening the net" of social control. The author's detailed analysis of decreasing imprisonment and the expansion of alternatives to imprisonment in Ontario during the post-World War II draws upon extensive documentary research and interviews with former corrections officials. The changing climates of opinion and socioeconomic factors that facilitated decarceration are charted. The author concludes that with the increasing use of probation as an alternative to imprisonment, prison populations were reduced; "net- widening" did not occur while prison populations remained the same or increased, as some researchers have charged has been the case when supposed alternatives to imprisonment have been adopted. The author concludes that alternatives to incarceration can have their intended effects if they are well conceived and monitored to ensure that they are implemented and maintained according to the values that governed their conception. By situating the analysis in the context of theoretical and political arguments about the possibility of decarceration, the author provides a stimulus to the development of progressive penal politics in all western countries. 27 figures, 17 tables, chapter notes, a 560-item bibliography, and a subject index