From Darwin to Hitler elucidates the revolutionary impact Darwinism had on ethics and morality. Weikart demonstrates that many leading Darwinian biologists and social thinkers in Germany believed that Darwinism overturned traditional Judeo-Christian and Enlightenment ethics, especially the view that human life is sacred. Many of these thinkers supported moral relativism, yet simultaneously exalted evolutionary 'fitness' (especially intelligence and health) as the highest arbiter of morality. Darwinism played a key role in the rise not only of eugenics, but also euthanasia, infanticide, abortion, and racial extermination. This thinking had its biggest impact on Germany, since Hitler built his view of ethics on Darwinian principles, not on nihilism as popularly believed.