Reuben Swinburne Clymer (November 25, 1878 - June 3, 1966) was an American occultist and modern Rosicrucian Supreme Grand Master of the FRC (Fraternitas Rosae Crucis), perhaps the oldest continuing Rosicrucian organization in the Americas. He practiced alternative medicine, and wrote and published works on it as well as (his version of) the teachings of Paschal Beverly Randolph (1825-1875), alchemy, nutrition, religion, sex magic and spiritualism. This led to a number of conflicts with Harvey Spencer Lewis (1883-1939) and the AMORC (Ancient Mystical Order Rosae Crucis), FUDOSI, Aleister Crowley, and even the American Medical Association.
