The American Civil War battle at Antietam, Maryland, on 17 September 1862, has been called the bloodiest day of that conflict. Confederate General Lee’s invasion of the North was repulsed, and when the fighting ended, the course of the Civil War had been greatly altered. This victory by the North moved President Abraham Lincoln to issue The Emancipation Proclamation, freeing all slaves in states then in rebellion against the Union. This 1960 publication is number 31 in the Historical Handbook series put out by the U.S. National Park Service. Print edition contains valuable maps that inform on troop movements. The author was a World War I veteran, a noted Civil War historian, and chief historian for the Gettysburg National Military Park in the 1950s and 1960s. - Summary by David Wales