A propaganda film made during the Spanish Civil War in support of the Republican government against the rebellion by Gen. Francisco Franco's forces who were backed by Nazi Germany and Fascist Italy. The film would have been seen by those making it as a documentary.
| Writing | Prudencio de Pereda | Writer |
| Writing | Archibald Macleish | Writer |
| Writing | John Dos Passos | Writer |
| Directing | Joris Ivens | Director |
| Writing | Lillian Hellman | Writer |
| Writing | Joris Ivens | Writer |
| Writing | Ernest Hemingway | Writer |
| Editing | Helen van Dongen | Editor |
| Sound | Virgil Thomson | Music |
| Crew | John Fernhout | Cinematography |
| Sound | Marc Blitzstein | Music Arranger |
