At the outbreak of the Civil War, Daniel Withum Sawtelle was a young man working on his family's farm in the north woods of Maine. The Republican son of a Democrat, he initially took little notice of a war he assumed would be over almost as soon as it started. As the conflict wore on, however, he began to disagree vehemently with his father about the future of the nation. Finally, in February 1862, he enlisted in the Eighth Maine Infantry. Fifty years later, Sawtelle drew on his wartime correspondence to compile a memoir of his experience.

All's for the Best combines Sawtelle's memoir with...