Can there be universal moral principles in a culturally and religiously diverse world? Are such principles provided by a theory of natural law? Jacques response to both questions is "yes".These essays, selected from the writings of one of the most influential philosophers of the past hundred years, provide a clear statement of Maritain's theory of natural law and natural rights. Maritain's ethics and political philosophy occupies a middle ground between the extremes of individualism and collectivism. Written during a period when cultural diversity and pluralism were beginning to have an impact on ethics and politics, these essays provide a defense of natural law and natural right that continues to be timely.The first essay introduces Maritain's theory of connatural knowledge -- knowledge by inclination -- that lies at the basis of his distinctive views on moral philosophy, aesthetics, and mystical belief. The second essay gives Maritain's principal metaphysical arguments for natural law as well as his account of how that law can be naturally known and universally held.The third essay in this collection explains the roots of the natural law and shows how it provides a rational foundation for other kinds of law and for human rights. In the fourth essay, reflecting his personalism and integral humanism, Maritain indicates how he extends his understanding of human rights to include the rights of the civic and of the social or working person.