By the late summer of 1862, it appeared as though the United States would be permanently split in two, and by the beginning of September, General Robert E. Lee's Army of Northern Virginia was on the doorstep of Washington, D.C. Panicked and defeated Federal soldiers huddled behind the capital’s defenses. Rather than attacking the city, Lee turned his attention north into Maryland, seeking a decisive battlefield victory to influence public opinion at home and diplomatic opinion overseas. Major General George B. McClellan led the reorganized Army of the Potomac into the state to meet Lee.Over a span of 18 days, the two armies fought four significant battles, including the climactic engagement along Antietam Creek outside Sharpsburg on September 17, 1862. The battle there still holds the distinction as the bloodiest single day in American military history. Forced from Maryland, Lee withdrew into Virginia, leaving President Abraham Lincoln free to follow up this strategic victory with the preliminary Emancipation Proclamation, a measure that changed the nature of the American Civil War.Copious illustrations and maps paired with a detailed text, this account of the Maryland campaign will have wide appeal.