A scholar’s foremost debt is to the libraries and archives whence comes the raw material for a book. I did most of the research for this book at the Firestone Library of Princeton University, whose resources on the American Civil War are excellent. The collections in the library of Antietam National Battlefield also immeasurably enriched the book; I am especially grateful to Ted Alexander, chief historian at Antietam National Battlefield, for his guidance in using these collections. To John Hennessy, assistant superintendent of Fredericksburg-Spotsylvania National Military Park and an outstanding historian as well, I owe a debt of gratitude beyond my power to express for his generosity in sharing his research notes on the Army of the Potomac. Nicholas Picerno of Claremont, New Hampshire, kindly gave me permission to quote from a letter in his possession written by Captain George H. Nye of the 10th Maine. Manuscript collections at the Library of Congress, the Huntington Library, the Illinois State Historical Library, and the Western Reserve Historical Society also provided important material; I thank the staffs of these repositories for their assistance.
David Hackett Fischer, my co-editor of the series of which this volume is a part, Pivotal Moments in American History, and our editor at Oxford University Press, Peter Ginna, read the manuscript and improved it greatly with their suggestions, as did Jennifer Weber, a graduate student at Princeton University. I greatly appreciate their help. Joellyn Ausanka at Oxford University Press expertly shepherded the manuscript through the publication process. To my wife, Patricia McPherson, I express my greatest thanks, and my love, for her work as a research assistant, proof-reading partner, and partner for life.