General Abner Doubleday (1819-1893) is best known as the man who "invented" baseball, but his admirable service on behalf of the Union earned him a reputation as a solid commander and patriot. He saw action at Fort Sumter where he aimed the first gun fired against the rebellion; at Antietam, Fredericksburg, and Chancellorsville, where he lead the First and later the Third Divisions of the First Corps of the Army of the Potomac; and finally at Gettysburg, where he commanded the entire First Corps after the death of General Reynolds early in the morning of the first day. Facing powerful...