Henry Havelock Ellis (1859-1939), English physician and writer. Ellis is best remembered for his highly controversial Studies in the Psychology of Sex, which was published in seven volumes between 1897 and 1928. This was a study of human sexual impulses, and was one of the first works to discuss sexual responses and problems. In it, Ellis stated that masturbation was harmless, that homosexuality was not an illness and that the female sexual response was normal. The work was banned for some time, and later restricted only to doctors, but Ellis became a champion of female equality and sexual liberation.