The Brothers' War

Four cavalry officers contend in the American Civil War: on the Union side, Captain Weismann, ardent abolitionist; Lieutenant, later Captain Maxwell; Allen Stevens, who rises to regimental command; and their Rebel nemesis, General Jack Rowell. There is a significant interaction between any two of the four.
Weismann wants revenge on Rowell for a brother's death. Maxwell is a disappointed portrait artist turned newspaperman, who matures as the war progresses. Rowell is colorful and equally given to dueling with sabres or insults. Stevens, a Virginian, must combat conflicting emotions, self doubt, and sometimes his own associates as well as the military enemy, and his reticence about his past leads to doubts in his subordinates as well.
The novel is in the form of letters from Maxwell to be printed in the hometown Elyria, Ohio newspaper. It follows the career of the Sixth Ohio Volunteer Cavalry and covers raising and training the troops, action in Virginia, camp life, the cavalrymen's winning their spurs, and eventual triumph.