A fascinating narrative-and a bold new thesis in the study of the Civil War-that suggests Robert E. Lee had a heretofore undiscovered strategy at Gettysburg that, if successful, could have crushed the Union forces and changed the outcome of the war.The Battle of Gettysburg is the pivotal moment when the Union forces repelled perhaps America's greatest commander-the brilliant Robert E. Lee, who had already thrashed a long line of Federal opponents-just...