Original and typescript of diaries (1862-1865) written while Boston was serving in Company H, 20th Michigan Infantry. The entries are chiefly descriptions of army life and battles in the campaign of Fredericksburg, first and second Kentucky campaigns, Vicksburg, the Wilderness, and Petersburg. National Park Service maps with a synopsis of the campaigns have been added to the typescript copy. The April 22, 1863 entry speaks of Frank Thompson (Sarah E. E. Seelye) as their brigade postmaster. The collection also contains thirty-seven letters (Jan. 1863-Apr. 1865) written to his aunts while Boston was serving in the 20th Michigan Infantry. He was sick and in hospital camps before Petersburg; once there, he gives accounts of activities there (Sept. 1864-Apr. 1865): picket duty, building fortifications, battles. He comments on food, the coming election, an African American regiment, General Burnside, the Sanitary and Christian Commissions, boxes from home, prisoners, the draft, and the reaction to the death of Lincoln. He describes two Thanksgiving dinners, and especially the fall of Petersburg. The collection also include's Boston's discharge certificate from the Union Army.