Walter Scheidel is the Dickason Professor in the Humanities, Professor of Classics and History, and Kennedy-Grossman Fellow in Human Biology at Stanford University, California. He is the author or editor of fifteen books on the ancient world, including The Cambridge Companion to the Roman Economy (Cambridge, 2012). His work, which has focused on ancient social and economic history, historical demography, and the history of empire, has been widely recognized for its innovative quantitative and comparative modelling, cross-cultural scope, and transdisciplinary breadth across the social sciences and life sciences.