ne afternoon 40 years ago, soon after beginning graduate work in history at the University of Virginia, I was sitting at a study carrel with a pile of books and a stack of index cards. The latter, I had learned, was one of the historian's most important tools—so important, in fact, that a renowned professor whose specialty was the Austro-Hungarian army devoted an entire class to telling us how to fill one in correctly. Now this strikes me as comical, but back then it struck me as comforting: having studied philosophy as an undergrad, I yearned for the kind of clarity custom-made for a three-by-five card. Whereas philosophical questions led only to more questions, historical questions led to the archives, where answers waited to be unearthed. Deep down, I believed what my professor believed—that we could know the past as it really
