istory is the account of vast social movements and cultural changes. To be sure, individuals play their part. But they are usually understood to be products of their times. The Reformation, though, whose five-hundredth anniversary we observe this year and whose impact on not only the church but the world has been monumental, was largely precipitated by one man: Martin Luther. Yes, vast social movements and cultural changes were at work in sixteenth-century Europe. But Luther caused many of them, such as the educational explosion that would lead to universal literacy, the rise of the middle class, and eventually democratic...