Pierpont Stackpole was a Boston lawyer who in January 1918 became aide to Lieutenant General Hunter Liggett, soon to be commander of the first American corps in France. Stackpole's diary, published here for the first time, is a major eyewitness account of the American Expeditionary Forces' experience on the Western Front, offering an insider's view into the workings of Liggett's commands, his day-to-day business, and how he orchestrated his commands in trying and confusing situations. Hunter Liggett did not fit John J. Pershing's concept of the trim and energetic officer, but Pershing entrusted to him a corps and then an army command. Liggett assumed leadership of the U.S. First Army in mid-October of 1918, and after reorganizing, reinforcing, and resting, the battle-weary troops broke through the German lines in a fourth attack at the Meuse-Argonne--accomplishing what Pershing had failed to do in three previous attempts. The victory paved the way to armistice on November 11. Liggett has long been a shadowy figure in the development of the American high command. He was "Old Army," a veteran of Indian wars who nevertheless kept abreast of changes in warfare and more than other American officers was ready for the novelties of 1914-1918. Because few of his papers have survived, the diary of his aide--who rode in the general's staff car as Liggett unburdened himself about fellow generals and their sometimes abysmal tactical notions--provides especially valuable insights into command within the AEF. Stackpole's diary also sheds light on other figures of the war, presenting a different view of the controversial Major General Clarence Edwards than has recently been recorded and relating the general staff's attitudes about the flamboyant aviation figure Billy Mitchell. General Liggett built the American army in France, and the best measure of his achievement is this diary of his aide. That record stands here as a fascinating and authentic look at the Great War.