Henry Havelock Ellis[needs IPA] (2 February 1859 – 8 July 1939) was an English 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.

Ellis was among the pioneering investigators of psychedelic drugs and the author of one of the first written reports to the public about an experience with mescaline, which he conducted on himself in 1896.

In April 1875, Ellis sailed on his father's ship for Australia; soon after his arrival in Sydney, he obtained a position as a master at a private school.

Some of them I should doubtless have reached without the aid of the Australian environment, scarcely all, and most of them I could never have achieved so completely if chance had not cast me into the solitude of the Liverpool Range.

His training was aided by a small legacy[4] and also income earned from editing works in the Mermaid Series of lesser known Elizabethan and Jacobean drama.

[4] He joined The Fellowship of the New Life in 1883, meeting other social reformers Eleanor Marx, Edward Carpenter and George Bernard Shaw.

Together with Magnus Hirschfeld, Havelock Ellis is considered a major figure in the history of sexology to establish a new category that was separate and distinct from homosexuality.

[13] Aware of Hirschfeld's studies of transvestism, but disagreeing with his terminology, in 1913 Ellis proposed the term sexo-aesthetic inversion to describe the phenomenon.

Ellis explained:[14] On the psychic side, as I view it, the Eonist is embodying, in an extreme degree, the aesthetic attitude of imitation of, and identification with, the admired object.

As in the Freudian tradition, Ellis postulated that a "too close attachment to the mother" may encourage eonism, but also considered that it "probably invokes some defective endocrine balance".

[14] In November 1891, at the age of 32, and reportedly still a virgin, Ellis married the English writer and proponent of women's rights Edith Lees.

He served as vice-president to the Eugenics Education Society and wrote on the subject, among others, in The Task of Social Hygiene: Eventually, it seems evident, a general system, whether private or public, whereby all personal facts, biological and mental, normal and morbid, are duly and systematically registered, must become inevitable if we are to have a real guide as to those persons who are most fit, or most unfit to carry on the race.The superficially sympathetic man flings a coin to the beggar; the more deeply sympathetic man builds an almshouse for him so he need no longer beg; but perhaps the most radically sympathetic of all is the man who arranges that the beggar shall not be born.In his early writings, it was clear that Ellis concurred with the notion that there was a system of racial hierarchies, and that non-western cultures were considered to be "lower races".

[18] In a debate in the Sociological Society, Ellis corresponded with the eugenicist Francis Galton, who was presenting a paper in support of marriage restrictions.

"[18] Instead, because unlike domesticated animals, humans were in charge of who they mated with, Ellis argued that a greater emphasis was needed on public education about how vital this issue was.

He continues by stating that, even in the early development and lower functional levels of the genitalia, there is a wide range of variation in terms of sexual stimulation.

Ellis states in his 1897 book Studies in the Psychology of Sex, that auto-eroticism ranges from erotic day-dreams, marked by a passivity shown by the subject, to "unshamed efforts at sexual self-manipulation witnessed among the insane".

[24] Ellis believed that the sense of smell, although ineffective at long ranges, still contributes to sexual attraction, and therefore, to mate selection.

Ellis states that with warmer climates come a heightened sensitivity to sexual and other positive feelings of smell among normal populations.

[19] However, Ellis noted that birth control could not be used randomly in a way that could have a detrimental impact by reducing conception, but rather needed to be used in a targeted manner to improve the qualities of certain 'stocks'.

Ellis argued that birth control was the only available way of making eugenic selection practicable, as the only other option was wide-scale abstention from intercourse for those who were 'unfit'.

In 1909, regulations were introduced at the Cantonal Asylum in Bern which allowed those deemed 'unfit' or with strong sexual inclinations to be subject to mandatory sterilization.

[28] However, already in his time, Ellis was witness to the rise of vasectomies and ligatures of the fallopian tubes, which performed the same sterilization without removing the whole organ.

In these cases, Ellis was much more favorable, yet still maintaining that "sterilization of the unfit, if it is to be a practical and humane measure commanding general approval, must be voluntary on the part of the person undergoing it, and never compulsory.

Rather, Ellis also considered the practicality of the situation, hypothesizing that if an already mentally unfit man is forced to undergo sterilization, he would only become more ill-balanced, and would end up committing more anti-social acts.

Furthermore, he supported adding ideas about eugenics and birth control to the education system in order to restructure society, and to promote social hygiene.

"[28] Ellis was among the pioneering investigators of psychedelic drugs and the author of one of the first written reports to the public about an experience with mescaline, which he conducted on himself in 1896.

He consumed a brew made of three Lophophora williamsii buds in the afternoon of Good Friday alone in his set of rooms in Temple, London.

During the experience, lasting for about 12 hours, he noted a plethora of extremely vivid, complex, colourful, pleasantly smelling hallucinations, consisting both of abstract geometrical patterns and objects such as butterflies and other insects.

[32][33] The title of the second article alludes to an earlier work on the effects of mind-altering substances, an 1860 book Les Paradis artificiels by French poet Charles Baudelaire (containing descriptions of experiments with opium and hashish).