The history of eugenics has traditionally been associated with genetics and biology. In this path-breaking book, Paul-André Rosental thoroughly revises this interpretation by showing that eugenics was just as closely connected to the history of psychology. Far from disappearing after the defeat of Nazism, eugenics has continued to exert an influence into the present through the psychology of personal development and liberal-democratic ideals of personal fulfilment. This extraordinarily original and deeply researched book demonstrates this by tracing an experiment conducted in France until the 1980s that became both a model and a source of hope for eugenicists around the world. By examining the reasons for its support by public authorities, Rosental reconstructs the enduring influence that eugenics, beginning with the New Deal, exercised over the expansion of public policies on both sides of the Atlantic.