This paper briefly summarizes current knowledge about Reduced Environmental Stimulation Therapy (REST). Major effects consistently produced by REST include (a) superlearning, (b) optimal physiological and psychological functioning, and (c) diminished denial and defensiveness. Persons showing greatest impairment or psychological disturbance prior to REST typically show the greatest "improvement" or change toward optimal levels of functioning afterward. REST facilitates natural homeostatic processes. Despite three decades of overwhelmingly positive research findings, REST technology has thus far received little understanding or acceptance. Common misconceptions about REST (formerly known as "sensory deprivation") are critically assessed and shown to be unfounded.