Morality based on natural law has a long tradition, and has proven to be quite resilient in the face of numerous attacks and challenges over the years. Those challenges are no less serious today, which leads one to ask if natural law is still a viable foundation for ethics. Craig Boyd provides a contemporary defense of natural law theory against modern challenges from the arenas of science, religion, culture, and philosophy. In his analysis, he defends many of the classical elements of natural law, but also takes into account the contributions of scientific discoveries about human nature. He concludes that natural law is a necessary but not sufficient basis for ethics that must be accompanied by a theory of virtue.