During the Civil War, letters between soldiers and their families were critical to morale on the frontlines and on the home front — they were nearly as important as ammunition. To ensure that the military mail was delivered, the U.S. Post Office Department deployed Special Agents across the country to deal with the millions of letters that were unleashed on the postal system. Arguably, the most important of these was Absalom Hanks Markland, who straddled the civilian and military worlds while creating the foundations for the military mail system of today. After the war, his swift response to Ku Klux Klan violence sparked passage of a landmark civil rights law. He was famous throughout the country during his lifetime, but forgotten until Delivered Under Fire, his first biography.