For thousands of years, people have used nature to justify their political, moral, and social judgments. Such appeals to the moral authority of nature are still very much with us today, as heated debates over genetically modified organisms and human cloning testify. This work offers a wide ranging account of how people have used nature to think about what counts as good, beautiful, just, or valuable. The eighteen essays cover a diverse array of topics, including the connection of cosmic and human orders in ancient Greece, medieval notions of sexual disorder, early modern contexts for categorizing individuals and judging acts as "against nature," race and the origin of humans, ecological economics, and radical feminism. The essays also range widely in time and place, from archaic Greece to early twentieth-century China, medieval Europe to contemporary America. This work provides a sustained historical survey of its topic.