Revealing the mind-set of a soldier seared by the horrors of combat even as he kept faith in his cause, Last to Leave the Field showcases the private letters of Ambrose Henry Hayward, a Massachusetts native who served in the 28th Pennsylvania Volunteer Infantry.

Hayward's service, which began with his enlistment in the summer of 1861 and ended three years later following his mortal wounding at the Battle of Pine Knob in Georgia, took him through a variety of campaigns in both the Eastern and Western theaters of the war. He saw action in five states, participating in the battles...