Walter Nugent has been Andrew V. Tackes Professor of History at the University of Notre Dame since 1984. His earlier books include The Tolerant Populist: Kansas Populism and Nativism, Money and American Society 1865-1880, Structures of American Social History, and Crossings: The Great Transatlantic Migrations, 1870-1914. Forthcoming is a history of the people of the American West.

Martin Ridge, former president of the Western History Association and the Pacific Coast Branch of the American Historical Association, is Senior Research Associate in the Huntington Library. He is former editor of The Journal of American History and co-author with Ray Allen Billington of Westward Expansion: A History of the American Frontier and America's Frontier Story: A Documentary History of Westward Expansion.