On June 10, 1863, the lead troops of General Robert E. Lee’s Army of Northern Virginia left the army’s staging area near Culpeper Court House, Virginia and began a march northward. Their destination: Pennsylvania – where Lee hoped to win a major battle on Northern soil and end the Civil War with a Southern victory. Soon his army would be trailed by his main Northern adversary, the Federal Army of the Potomac. Ahead of both armies, across the Potomac River and in the heartland of southern Pennsylvania, lay the quiet crossroads town of Gettysburg, which would become the site of...