In the only book to date to explore the period between the 1859 publication of Darwin's 'Origin Of Species' and the discovery of Gregor Mendel's experiments in genetics, John S. Haller, Jr. shows the relationship between scientific 'conviction' and public policy. He focuses on the numerous liberally educated American scientists who were caught up in the triumph of evolutionary ideas and who sought to apply those ideas to comparative morality, health, and the physiognomy of nonwhite races.