Susan Blackmore’s Beyond the Body provides a comprehensive historical overview of out-of-body experience (OBE) research. She surveys anecdotal case studies, including cross-cultural comparisons of OBEs, and concludes that there are no essential experiential differences between spontaneous OBEs and voluntarily-induced OBEs. Blackmore considers how common OBEs are in the population at large, reviews proposed techniques for inducing OBEs, surveys attempts to identify specific brain states corresponding to OBEs, and briefly surveys anecdotal case studies of deathbed visions and near-death experiences (see Blackmore’s Dying to Live for a more detailed analysis).
Blackmore also reviews studies of similarities between hallucinations and OBEs, analyzes experiments carried out since the late 1960s to determine if OBE subjects can retrieve information from locations out of sensory range of their physical bodies, surveys attempts to detect physical effects of ‘out-of-body persons’ during OBEs, and provides an overview of theories of the OBE and how those theories compare with the empirical evidence. Beyond the Body concludes with Blackmore’s own psychological theory of OBEs, spelling out its falsifiable predictions. Blackmore also surveys early 20th century attempts to detect a loss of weight from the body at death (implying a departure of the soul) and attempts to photograph the soul leaving the body at or soon after death.