Mrs. Leonora Piper (1859-1950) was one of the most famous mediums who ever lived. She attracted a large following, and even aroused the curiosity of the renowned psychologist and skeptic William James. Avoiding the more obvious tricks of levitating tables and floating trumpets, Mrs. Piper would go into trances, during which she was allegedly taken over by spirits who controlled her voice and directed her hand to write messages.

Studies in Spiritism is the verbatim record of six seances which psychologist and psychic researcher Dr. Amy Tanner attended with Dr. G. Stanley Hall in 1909, when Mrs. Piper was at the height of her fame. Although they went in with open minds, Tanner and Hall came away convinced that, while Mrs. Piper may well have been a classic case of a person with multiple personalities who emerged from her unconscious mind during these sittings, she was not above using deliberate deception. This monumental study still stands as a classic skeptical account of mediums and their methods.