Duff Levi Bird Duff 
To Petersburg with the Army of the Potomac [PDF ebook] 
The Civil War Letters of Levi Bird Duff, 105th Pennsylvania Volunteers

The letters of Levi Bird Duff present a perceptive picture of life in the Army of the Potomac from 1861 to 1864. They are unusual for their literacy, descriptions and continuity, the strength of opinions expressed, and their source: a private who rose to the rank of lieutenant colonel, thus a witness of the army at several levels. Leadership, organizational, weather, and morale problems that plagued Union troops are made clear. Written only for the eyes of Duff’s love, the messages reflect the tension experienced by many soldiers between the conflicting calls of duty and affection.