Antietam is the eagerly awaited second volume of Ezra Carman's magisterial The Maryland Campaign of September 1862. Many authors have written about the climactic September 17 battle of the 1862 invasion of Maryland, but it is impossible to do so without referencing Carman's sweeping and definitive maps and 1,800-page manuscript. His work guides every Civil War historian and comprises the basis of the National Park Service's interpretive programs at Antietam. Indeed, even the basic layout of the National Park battlefield was based upon Carman's groundbreaking work. Carman had the advantage of not only participating in the battle as a colonel in the Union army, but knowing, corresponding, and conversing with hundreds of Northern and Southern soldiers from corps commanders all the way down to privates. Over the decades he amassed a vast collection of letters, maps, and personal memoirs from many key participants. He used this treasure trove of firsthand accounts to create his compelling n