Eugenics is the branch of biology concerned with the improvement of hereditary qualities in humans. It draws scientists into direct contact with social and political policy makers. Yet, eugenic movements which have been mainly implemented by politicians, often differ significantly from the original aims of the scientists. The four contributors to this volume examine the eugenic movements in Germany, France, Brazil, and the Soviet Union. The scientific components of those programmes are considered alongside the social, religious, and political forces which significantly altered the original scientific goals. The book opens up new and comparative perspectives on the history of eugenics and the social aspects of science in general.