The author presents a detailed psychological case study of a woman medium who, during trance states, produces automatic speech and writing, invents an elaborate Martian language and mythology, and reenacts several distinct imaginative cycles (Martian, Hindoo, royal) with vivid personae. He documents seances, somnambulistic behavior, telepathic impressions, lucid perceptions, physical phenomena reported at sittings, and purported retrocognitive and diagnostic instances, then analyzes the psychogenesis of alternate personalities such as Leopold and the sources of the symbolic material. Linguistic examination addresses phonetics, grammar, syntax, and vocabulary of the invented language, while the book weighs naturalistic explanations and explores the subliminal mental processes underlying mediumistic manifestation.