Born into a distinguished military family, Fitz John Porter (1822-1901) was educated at West Point and breveted for bravery in the war with Mexico. Already a well-respected officer at the outset of the Civil War, as a general in the Union army he became a favorite of George B. McClellan, who chose him to command the Fifth Corps of the Army of the Potomac. Porter and his troops fought heroically and well at Gaines's Mill and Malvern Hill. His devotion...