The most definitive study of this phenomenon, this book was first published in 1921. The author, a German philosophy professor, has compiled a virtual anthology of arcane literature including case studies and ancient accounts dating from its first appearance in the Scriptures. General topics cover its external signs, the subjective state of the possessed, the distribution of spontaneous possession in both primitive and higher civilizations throughout the world, exorcism and shamanism. The book is well documented and the immense research that Mr. Oesterreich has done will help this book remain a classic in the field. The subject certainly carries its own fascination for the layman although it is primarily directed to the student of psychology.