John Dos Passos per Daniel Aaron: Chapter 15 of Aaron's "Writers on the Left," which discusses Dos Passos's early career.
Modernist Portraits: John Dos Passos: The "American Passages: A Literary Survey" web site offers a brief biography of Dos Passos, artifacts, teaching tips, discussion questions, and an instructor's guide.
One Man's Initiation: 1917: First novel based largely on Dos Passos' own wartime experiences in France and Italy and published in London in 1920.
Ross Lockridge, Jr. on John Dos Passos: A statement of some reasons for using "U.S.A." by John Dos Passos as a representative of the modern American novel (1943) by Ross Lockridge, Jr.