The first year of the American Civil War wasn’t a great one for the Union Army. Losses at places like Bull Run and Ball’s Bluff overshadowed a string of smaller but equally important battles across the country. President Abraham Lincoln’s general-in-chief, George B. McClellan, was highly regarded by his men but was difficult to deal with, increasingly insubordinate, and failed to follow up on his victories.  However, a shining star was beginning to emerge in the Western Theater of the war....