Letterbooks containing official correspondence signed by Leffingwell during his term as U.S. assistant secretary of the treasury and by other U.S. Dept. of the Treasury officials. Subjects include war debts and loans, postwar financing, and bond drives. Correspondents include Gordon Auchincloss, Newton Diehl Baker, Bernard M. Baruch, Édouard de Billy, John Burke, Bainbridge Colby, Oscar Terry Crosby, Josephus Daniels, Thomas Watt Gregory, W.P.G. Harding, Herbert Hoover, Robert Lansing, Alexander Legge, Sir Hardman Lever, Breckinridge Long, conte Vincenzo Macchi di Cellere, William G. McAdoo, A. Mitchell Palmer, Frank L. Polk, Benjamin Strong, André Tardieu, and Woodrow Wilson.