Alfred Henry Tipper (12 July 1867 – 2 April 1944), also known by the pseudonyms Professor Tipper and H.D. (reported to be an initialism for Henry Dearing or Harold Deering), was an Australian showman, competitive and endurance cyclist, and outsider artist. His combined interests in mechanics, fitness and entertainment led to a long career as a trick cyclist and builder of miniature bicycles.