The idea of the therapeutic community (TC) recurs throughout history implemented in different incarnations. In its contemporary form, two major variants of the TC have emerged. One, in social psychiatry, consists of innovative units and wards designed for the psychological treatment and management of socially deviant psychiatric patients within mental hospital settings. In the other form, TCs have taken are as community-based residential treatment programs for addicts and alcoholics. This chapter explores the sources and evolution of these communities to illustrate how they contribute to the theoretical framework of the TC. It describes the direct and indirect influences shaping the essential elements of the modern TC. The early religious influences on the Oxford group and Alcoholics Anonymous (AA) reappear as elements of the modern TC. The search for an “essential TC” reveals a universal idea recurring in various forms throughout history: that of healing, teaching, support, and guidance through community.