Glossolalia or "speaking in tongues" has evoked much speculation as to its causes and meanings. Primarily occurring in instances of religious fervor, glossolalia's recent linkage to psychopathic behavior has prompted numerous studies by social and behavioral scientists. This book summarizes and interprets all of the research done on this phenomenon. The authors explore the different types and settings of glossolalic expression in contemporary Western religion and consider the phenomenon from the perspectives of sociology, psychology, and linguistics. Numerous case studies are included as well as an abundance of the authors' own research on the subject. Glossolalia will be of particular interest to those in the fields of sociology and psychology and to those engaged in counseling glossolalic individuals.