T HE HISTORY OF EUGENICS is one of a reciprocal involvement of science and politics. Simply put, that history can be characterized as beginning with two scientific theories, evolutionary theory and its complement, the theory of human heredity. Taken up by political discourse, these theories helped to create or crystallize concerns about the hereditary quality of the human stock. They delineated and helped to focus political concerns about population policy and control. Scientists used eugenics as a vehicle for their political convictions and social biases, just as politicians used its scientific framework, sketchy as it was, to advance their particular causes. It was only in Germany, however, that the small community of race hygienists (as eugenicists called themselves there), seeking status and recognition, formed a coalition with politicians of the conservative and radical right. This coalition enhanced the political influence of race hygienists and aided the implementation of many of their ideas. The subsequent moral catastrophe had repercussions far beyond the German community, forcing eugenics-minded geneticists all over the world to strive for a sharper demarcation between science and politics. Their efforts eventually resulted in a fundamental change in their original program: human genetics thereafter renounced all claims to improving the gene pool of the human race as a whole and instead concentrated on the cure of genetic diseases on an individual basis. This study does not encompass the entire development of eugenics in Germany. It focuses on the crucial role of an institute in Berlin, the Kaiser Wilhelm Institute (KWI) for Anthropology, Human Heredity and Eugenics (KaiserWilhelm-Institut fur Anthropologie, Menschliche Erblehre und Eugenik), which became the single most important institution for race hygiene in Germany. Although there were a number of other important centers devoted to various aspects of eugenics and race hygiene-such as the Institute for Genealogy and Demography under Ernst Rudin in Munich, which was part of the German Research Agency for Psychiatry and in 1924 became an institute in the Kaiser-Wilhelm-Gesellschaft (KWG)-the institute in Berlin was clearly the leading institution in the field between its foundation in 1927 and 1945. Given that the most eminent representatives of race hygiene, Eugen Fischer, Fritz Lenz, and Otmar