Christopher McKnight Nichols is professor of history and Wayne Woodrow Hayes Chair in National Security Studies, Mershon Center for International Security Studies, at the Ohio State University. An Andrew Carnegie Fellow and award-winning scholar and teacher, Nichols is the author or editor of six books, including Promise and Peril: America at the Dawn of a Global Age (2011) and Rethinking American Grand Strategy (2021). Nancy C. Unger, President of the Society for Historians of the Gilded Age and Progressive Era 2021-2023, is Professor of History at Santa Clara University. She is the author of the award-winning biographies Fighting Bob La Follette: The Righteous Reformer (2000; revised paperback 2008), and Belle La Follette: Progressive Era Reformer (2016). Her book Beyond Nature’s Housekeepers: American Women in Environmental History (2012), was a California Book Award Finalist.