The doughboys joined for patriotism and excitement. Some were aroused by the atrocity stories, others fought for democracy. Only a few clearly understood their motivations, like Lieutenant Philip Shoemaker, who fought "for freedom and justice to all":
- "If I am fortunate enough to come home alive after the war, I will be able to handle any kind of job, a better man than any one that has not been in the war. If I don't come back, I will of first had a chance to see the country, have a good time and be an AMERICAN soldier in the World War."
The 4 million doughboys were a cross section of the entire population of young men; they served an average of 12 months. Half went to Europe, staying an average of 5.5 months. Only 34% of the enlisted men were assigned to combat specialties. This was the first industrial war, and the Army's "tail" was twice as long as its "teeth." One third of the men were assigned as laborers or service workers (including 80% of the blacks); 22% were mechanics and craftsmen; 12% held clerical or technical jobs. Col. George Patton observed, "It is remarkable how much easier these [drafted] men are to teach than the old soldiers we used to have. They had no brains at all. These men have plenty."
- Gawne, Jonathan. Over There!: The American Soldier in World War I (1999)- 83 pages, heavily illustrated
- Grotelueschen, Mark Ethan. The AEF Way of War: The American Army and Combat in World War I (2006) excerpt and text search
- Hallas, James H. Doughboy War: The American Expeditionary Force in World War I (2000) online edition
- Skilman, Willis Rowland. The A.E.F.: Who They Were, what They Did, how They Did it (1920) 231 pp; full text online
- Smith, Gene. Until the Last Trumpet Sounds: The Life of General of the Armies John J. Pershing (1999), popular biography.
- Snell, Mark A. Unknown Soldiers: The American Expeditionary Forces in Memory and Remembrance (2008)
- Thomas, Shipley. The History of the A. E. F. (1920), 540pp; full text online
- Votow, John. The American Expeditionary Forces in World War I (2005) - 96 pp; excerpt and text search
- Werner, Bret. Uniforms, Equipment And Weapons of the American Expeditionary Forces in World War I (2006)
- Ronald Schaffer, America in the Great War (1991) p. 182
- Schaffer, America in the Great War p. 183