Gertrude Stein used the phrase in conversation with Ernest Hemingway, supposedly quoting a garage mechanic saying to her, "You are all a lost generation."
The phrase signifies a disillusioned postwar generation characterized by lost values, lost belief in the idea of human progress, and a mood of futility and despair leading to hedonism.
"Lost generation" usually refers specifically to the American expatriate writers associated with 1920s Paris, especially Hemingway and Fitzgerald, and to a lesser extent T. S. Eliot and Ezra Pound.
"Gatsby believed in the green light, the orgastic future that year by year recedes before us. It eludes us then, but that's no matter- to-morrow we will run faster, stretch our arms farther... And one fine morning-- So we beat on, boats against the current, borne back ceaselessly into the past." - DAISY