There has been much attention devoted in recent years to the question of whether our moral principles can be related to our biological nature. This collection of new essays focuses on the connection between biology and foundational questions in ethics. The book asks such questions as whether humans are innately selfish, and whether there are particular facets of human nature that bear directly on social practices. This is the first book to offer this historical perspective on the relation of biology and ethics, and has been written by some of the leading figures in the history and philosophy of science, whose work stands very much at the cutting edge of these disciplines.