Tim O'Brien is an American novelist who served as a soldier in the Vietnam War. Much of his writing is about wartime Vietnam, and his work later in life often explores the postwar lives of its veterans.

A war novel or military fiction is a novel about war. It is a novel in which the primary action takes place on a battlefield, or in a civilian setting, where the characters are preoccupied with the preparations for, suffering the effects of, or recovering from war. Many war novels are historical novels.