From the Stonewall Brigade to the Iron Brigade, Americans have long been fascinated by the Civil War's most famous and legendary units, and many are familiar with the 20th Maine's defense of Little Round Top at the Battle of Gettysburg. But ironically, perhaps the most famous regiment of the entire war today is the 54th Massachusetts, which was one of the first and ultimately the best known regiment that consisted of black soldiers. Like most black soldiers, the 54th received discriminatory treatment from the Army, as white men on both sides were wary of trusting black soldiers in heavy...