The first medical text exclusively devoted to sexuality, though Kaan's views reflected religious, and other prejudices of the time. Digital facsimile of the 1844 edition from staatsbibliothek-berlin.de at this link.

Translated into English by Melissa Haynes, edited by Benjamin Kahan, as Heinrich Kaan's "Psychopathia Sexualis" (1844). Ithaca, NY: Cornell University Press, 2016.  "Heinrich Kaan's fascinating work—part medical treatise, part sexual taxonomy, part activist statement, and part anti-onanist tract—takes us back to the origins of sexology. He links the sexual instinct to the imagination for the first time, creating what Foucault called "a unified field of sexual abnormality." Kaan's taxonomy consists of six sexual aberrations: masturbation, pederasty, lesbian love, necrophilia, bestiality, and the violation of statues. Kaan not only inaugurated the field of sexology, but played a significant role in the regimes of knowledge production and discipline about psychiatric and sexual subjects. As Benjamin Kahan argues in his Introduction, Kaan's text crucially enables us to see how homosexuality replaced masturbation as the central concern of Euro-American sexual regulation...." (publisher).