Walters provides commentary on Diderot's translation of Shaftesbury's An Inquiry Concerning Virtue or Merit. By comparing the translation and notes, he demonstrates the evolution of Diderot's thought and artistic skill, discusses the difference between theism and deism, the question of universal order, and compares atheism with free thought. After an analysis of religious fanaticism and social and political abuses, he turns his attention to virtue, as it relates to happiness, objective values, the moral sense, the passions, and self-interest. A final chapter deals with the style of the Essai.