Henry Havelock Ellis (1859–1939) was an English physician, sexologist, and social reformer. He conducted pioneering research that led to his momentous seven-volume work Studies in the Psychology of Sex. His works on homosexuality, transgender psychology, narcissism and autoeroticism were groundbreaking. A supporter of women’s rights, sexual education, and sexual liberation, he did much to pave the way for researcher Alfred Kinsey and others.