Karsch-Haack's "Same-Sex Life of Primitive Peoples", 1911
A professor of zoology at the University of Berlin, Ferdinand Karsch-Haack (1853-1936) was on early member of the Scientific-Humanitarian Committee, the German homosexual emancipation organization headed by.. Dr. Magnus Hirschfeld. Although Karsch-Haack accepted the congenital theory of homosexuality advanced by his contemporaries, he reacted against the preponderance of medical studies, arguing that it was less important to understand homosexuality's etiology them its varied manifestations. This interest motivated his survey of "primitive" societies, which in turn led him to the conclusion that homosexuality is a universal and fundamentally natural phenomenon. Karsch-Haack planned a five-volume series on the ethnology of homosexuality which remained uncompleted. His Das gleichgeschlechtliche Leben der Naturvolker [The same-sex life of primitive peoples] did, however, appear in 1911. 
Over five hundred pages in length, it presents a comprehensive compilation of primary source materials on male homosexuality among the North and South American Indians, Australian aborigines, Malayans and Melanesians, Eskimos and other Arctic peoples, and' Black Africans. A short, though important, section on lesbianism is included. To the present day, Kerseh-Heeek's study remains the major source book on native homosexuality.
Jonathan Ned Katz, Gay American History: Lesbians and Gay Men in the U.S.A. (NY: Crowell, 1976) pg. 321.
- Ferdinand Karsch-Haaek, Das gleichgeschlechtliche Leben der Naturvolker (Munich: Reinhardt, 1911; photo reprint, N.Y.: Arno, 1975). Also see Clark Wisler on "The Berdache Cult" in "Societies and Ceremonial Associations in the Oglala Division of the Teton-Dakota," Anthropological Papers of the American Museum of Natural History, vol. 12 (1912), p. 92.