Elmer S. Prather

Elmer Sidney Prather (January 19, 1872 - September 14, 1877), also known as Professor Elmer Ellsworth Knowles, was an American author, lecturer, and mail-order peddler of correspondence courses and nostrums based on psychic and hypnotic powers, including his Knowles Radio-Hypnotic Crystal.

Selected Bibliography

 * "Professor Elmer E. Knowles' Complete System of Personal Influence and Healing (Six Complete Branches)" (National Institute of Sciences, 1899)
 * "Personal Power: Avenues to Its Acquisition" (Progress League, 1919)