As the "Great War" inspired much great poetry, including that of Siegfried Sassoon and Robert Graves, so did it inspire compelling prose. John Dos Passos volunteered to drive an ambulance in France during the First World War. The brutality of his experiences turned him against not only war, but capitalism and inspired him to write One Man's Initiation: 1917. (Goodreads)
John Roderigo Dos Passos, (January 14, 1896 – September 28, 1970) was an American novelist and artist active in the first half of the twentieth century. Born in Chicago, he graduated from Harvard College in 1916. He was well-traveled, visiting Europe and the Middle East, where he learned about literature, art, and architecture. During World War I, he was an ambulance driver for American volunteer groups in Paris and Italy before joining the United States Army Medical Corps. (Wikipedia)