As the originator of the Scottish school of "common sense" philosophy and the foremost contemporary critic of David Hume's moral skepticism, Thomas Reid (1710-1796) played a hitherto unknown role in applying the tradition of natural law to morality and politics. When Reid succeeded Adam Smith as professor of moral philosophy in Glasgow in 1764, he taught a course covering pneumatology (theory of mind), practical ethics, and politics. In presenting for the first time the philosopher's manuscript lectures and papers on practical ethics, Knud Haakonssen shows how these writings not only add depth to Reid's criticism of Hume but also clarify his own social, moral, and political thought. As a whole, Reid's Practical Ethics constitutes a most significant addition of source material for the study of the Scottish Enlightenment. The papers assembled here demonstrate the extent to which the moral philosophy of the Enlightenment was influenced by natural jurisprudence. At the same time they reveal Reid's involvement with republican, utopian, and radical themes and elucidate the relations between religion and politics in the Enlightenment. Haakonssen's introduction is the first substantial systematic treatment of Reid's moral-political thought, connecting it with his general philosophy and setting it in the context of his life and time.