Correspondence (chiefly 1877-1881), diaries and journals (1862-1889), and reports relating principally to the presidential administration and assasination of James A. Garfield. Includes ninety letters from Garfield to Rockwell relating to their friendship, investments in the Silver King Mining Company, controversy over the resignation of New York senator Roscoe Conkling, and Garfield's appointment of Rockwell as superintendent of public buildings in Washington, D.C. Rockwell's diaries describe his Civil War service as an aide to Gen. Don Carlos Buell, the federal occupation of Nashville, Tenn., battles of Shiloh and Corinth, Miss., campaigns in northern Alabama, the pursuit of Confederate Gen. Braxton Bragg in Kentucky, the death of Gen. William Nelson, and Buell's removal and reinstatement in the U.S. Army. Also included are reports of Rockwell's conversation with Garfield shortly before the latter's death and a letter describing the death of Abraham Lincoln, at which Rockwell was also present. Other correspondents include James M. Barney, Don Carlos Buell, Frank Abial Flower, Charles F. Manderson, William Henry Seward, and John M. Wilson.