Three research assistants provided essential help in locating and often shrewdly commenting on primary sources: David K. Johnson, Miles Becker, and Michael Allen. Allison Quinn provided last-minute help with sources. Antony Burton did fast and good work obtaining the images used. Several people read the manuscript, some more than once—Nadine Hubbs, David K. Johnson, George Chauncey, Marilyn Young, Lane Fenrich, and Charles Grench (my editor since my first book three decades ago) —and generously offered corrections, counsel, conversation, challenges, and encouragement. Others provided support, comments, and leads in conversations after reading parts of the manuscript or hearing versions in lectures. Research leaves underwritten by Northwestern University provided time for work on this book. Research funds, made possible by former students of Richard Leopold who endowed a chair in his honor, underwrote many of the costs involved. Chairs of the Northwestern history department and colleagues in it provided support in other ways. My partner, James Beal, and other family members endured many delays in this project and disruptions caused by it. I thank them for their patience and for their own insights into this history.