- The Lost Generation is the demographic cohort that reached early adulthood during World War I, and preceded the Greatest Generation. The social generation is generally defined as people born from 1883 to 1900, coming of age in either the 1900s or the 1910s. The term is also particularly used to refer to a group of American expatriate writers living in Paris during the 1920s. Gertrude Stein is credited with coining the term, and it was subsequently popularised by Ernest Hemingway, who used it in the epigraph for his 1926 novel The Sun Also Rises: “You are all a lost generation.” “Lost” in this context refers to the “disoriented, wandering, directionless” spirit of many of the war’s survivors in the early postwar period.