In researching and writing this book, I have been fortunate in the help and encouragement friends and colleagues have given me. Their collegiality and generosity constitute one of the most rewarding aspects of the enterprise and, of course, have improved the work immeasurably. My thanks go to Ira Berlin, Nigel Bolland, Michael Craton, Stanley Engerman, Peter Fearon, Barry Gaspar, Barry Higman, Howard Johnson, David Katzman, Woodville Marshall, August Meier, Philip Morgan, Richard Sheridan, Mary Turner, William Tuttle, Swithin Wilmot, and the late Neville Hall. They are responsible for many of the book's strengths, but, of course, none of its shortcomings.