Previously reported results of sensory-deprivation experiences, of which flotation REST is an instance, were dramatic, generally negative and ultimately unreliable. This book offers controlled systematic research on the effects of flotation REST. The papers in this collection were chosen from those presented at the first three international conferences on REST and fall into several categories. The major category concerns theoretical formulations for REST effects; other categories in the collection deal with experimental findings and clinical research in relation with flotation REST.