Henry Havelock Ellis (February 2, 1859 - July 8, 1939) was a English physician and psychologist, writer, and social reformer who studied human sexuality. He was co-author of the first medical textbook in English on homosexuality in 1897, and also published works on a variety of sexual practices and inclinations, including transgender psychology. He is credited with introducing the notions of narcissism and autoeroticism, later adopted by psychoanalysis. In 1891, 32 years old and still a virgin, Ellis married the English writer, Edith Lees. Their marriage was unconventional, as Edith Lees was openly lesbian. He suffered from impotence until the age of 60. He then discovered that he could become aroused by the sight of a woman urinating (urolangia). He lived to be 80 years old and died of natural causes.