In the same week that Union forces triumphed at Gettysburg, they also captured the river fortress at Vicksburg, Mississippi. Although much less memorialized than Gettysburg, the fall of Vicksburg was every bit as crucial to the Union cause. Pitting Ulysses S. Grant and William T. Sherman against John Pemberton and Joseph Johnston, the victorious Vicksburg Campaign helped revive a war-weary North, gave it absolute control of the Mississippi River,...