The inspiration for this book came from a graduate seminar on comparative eugenics movements in the early 1970s at the University of Pennsylvania. I was working on a dissertation about French views of Africans during the period of colonial expansion, and I decided to study whether eugenics in France was connected to racist attitudes at the end of the nineteenth century. This was not to be the case, alas, and I returned to complete the dissertation, publish it as a book, and take up my first teaching assignment.

When I returned to my investigation of eugenics, I uncovered a vast interconnection of movements that quickly took me in several new directions. Although race was not at the root of these movements – demography and health were – it was always present, and later became an important component. Of greater overall significance was the fact that the various movements for the biological regeneration of France in the twentieth century typified society's relation to science in the modern world that crossed national boundaries and continues to the present day. Because of the interest in eugenics and the social relations of science, and the importance of the comparative perspective, I have written this book to set forth the French experience in its broadest context. Rather than its being the last word on the subject, it will I hope prompt others to add, correct, and above all complete the study of the topic.

Work on this project has lasted for so long that it would be impossible to thank all of those who have helped.