John T. Farnham, a sharpshooter in the Union Army, wrote a substantial diary entry nearly every day during his three-year enlistment, sent over 50 long articles to his hometown newspaper, and mailed some 600 letters home. He described training, battles, skirmishes, encampments, furloughs, marches, hospital life, and clerkships at the Iron Brigade headquarters and the War Department. He met Lincoln and acquired a blood-stained cuff taken from his assassinated...