Henry Havelock Ellis was an English-French physician, eugenicist, writer, progressive intellectual and social reformer who studied human sexuality. He co-wrote the first medical textbook in English on homosexuality in 1897, and also published works on a variety of sexual practices and inclinations, as well as on transgender psychology. He developed the notions of narcissism and autoeroticism, later adopted by psychoanalysis.

Narcissism is a self–centered personality style characterized as having an excessive preoccupation with oneself and one's own needs, often at the expense of others.