“For generations, biographers have used the same methods to conduct research: they waded through the paper trail left by their subject, piecing together a life from epistolary fragments. Based on what they found, they might troll through newspapers from specific dates in the hope of finding coverage of their subject. There were no new-fangled technologies that promised to transform their research, no way of harnessing machines to reveal new layers of historical truth. That’s all starting to change.”