My commander-in-chief, Michael Watson, the capable and patient military history editor for Cambridge University Press, presented me with a formidable objective in late 2010: write a holistic history of the US Army’s role in World War I that examined diverse social, political, diplomatic, and military themes. At times during the past two years I have felt as if I were one of Pershing’s Doughboys attempting to navigate the unfamiliar and intricate German defenses at Meuse-Argonne. Indeed, their persistence was required to achieve my assigned mission.

Once the United States becomes a belligerent I address multiple themes, including the raising, training, transporting, and logistical support of a diverse force which included African and Native Americans as well as many other hyphenated Americans, coalition warfare (a new experience for the US military and political leadership), failures in war production, the interdependence of armed force and diplomacy, armed intervention in Russia, and the creation of an independent US force with its own strategical objectives. Although this narrative with its emphasis on leaders such as Pershing and Wilson generally embraces a top-down rather than a bottom-up approach, ordinary American soldiers are given their due by including their voices through the use of letters, memoirs, and other personal accounts. Finally, by placing the American Expeditionary Force’s role within the larger war, I avoid examining American participation exclusively from a US perspective.