This small volume is based upon three lectures on Eugenics delivered at Oberlin College in April, 1910. In preparing them for publication many extensions and a few additions have been made in order to present the subject more adequately and to include some very recent results of eugenic investigation. Few subjects have come into deserved prominence more rapidly than has Eugenics. Biologists, social workers, thoughtful students and observers of human life everywhere, have felt the growing necessity for some kind of action leading to what are now recognized as eugenic ends. Hitherto the lack of guiding principles has left us in the dark as to where to take hold and what methods to pursue. To-day, however, progress in the human phases of biological science clearly gives us clews regarding modes of attack upon many of the fundamental problems of human life and social improvement and progress, and suggests concrete methods of work.