He is the author of Retreat from Gettysburg: Lee, Logistics and the Pennsylvania Campaign, Cushing of Gettysburg: The Story of a Union Artillery Commander, and editor of The Civil War in Kentucky. He was the creator and first editor of the magazine The Civil War and was the first chairman of both the Gettysburg National Military Park Advisory Commission and the Perryville (Kentucky) Battlefield Commission. He organized and created the Perryville Battlefield Preservation Association