David Hume is widely regarded as the most important philosopher ever to write in English, but during his lifetime he was attacked as “the Great Infidel” for his skeptical religious views and deemed unfit to teach the young. In contrast, Adam Smith was a revered professor of moral philosophy, and is now often hailed as the founding father of capitalism. Remarkably, the two were best friends for most of their adult lives, sharing what Dennis Rasmussen calls the greatest of all philosophical friendships. The Infidel and the Professor is the first book to tell the fascinating story of the friendship of these towering Enlightenment thinkers—and how it influenced their world-changing ideas.