Zachary M. Schrag is Professor of History and Director of the MA Program in History at George Mason University. Schrag studies cities, technology, and public policy in the United States in the nineteenth, twentieth, and twenty-first centuries. He is the author of three books, The Great Society Subway: A History of the Washington Metro, and Ethical Imperialism: Institutional Review Boards and the Social Sciences, 1965-2009, both published by the Johns Hopkins University Press, and The Princeton Guide to Historical Research, published by Princeton University Press. A fourth book, The Fires of Philadelphia: Citizen-Soldiers, Nativists, and the 1844 Riots Over the Soul of a Nation, is scheduled to be released by Pegasus Books in June 2021.