In just two years it will be the five hundredth anniversary of the Protestant Reformation, traditionally marked by that day when an Augustinian monk and university professor named Martin Luther proposed 95 topics for academic debate at the University of Wittenberg. But what was the Protestant Reformation, really? Did it begin in 1517? How long did it last? Was there one reformation, or many? What were its consequences? And which of its consequences are overstated?