Eugenic thought and practice swept the world from the late nineteenth to the mid-twentieth century in a remarkable transnational phenomenon that informed social and scientific policy across the political spectrum, from liberal welfare measures in emerging social-democratic states, to feminist ambitions for birth control, to public health campaigns, to totalitarian dreams of the "perfectibility of man." This book dispels for uninitiated readers the automatic and apparently exclusive link between eugenics and the Holocaust: the popularity of eugenics in Japan, for example, comes as a surprise. It is the first world history of eugenics and an indispensable core text for both teaching and research in what has become a sprawling but ever more important field. Eugenics has accumulated generations of interest as part of the question of how experts think about the connections between biology, human capacity and policy. In the past and the present, eugenics speaks to questions of race, class, gender and sex, evolution, governance, nationalism, disability, and the social implications of science. In the current climate, where the human genome project, stem cell research, and new reproductive technologies have proven so controversial, the history of eugenics has much to teach us about the relationship between scientific research, technology, and human ethical decision-making. This volume offers both a nineteenth-century context for understanding the emergence of eugenics and a consideration of contemporary manifestations of, and relationships to eugenics. It is the definitive text for students and researchers to consult for careful and up-to-date summaries, new substantive fields where very little work is currently available (e.g. eugenics in Iran, South Africa, and South East Asia); transnational thematic lines of inquiry; the integration of literature on colonialism; and connections to contemporary issues.