In the late 1930s, John Steinbeck, Richard Wright, and Ernest Hemingway wrote novels that won critical acclaim and popular success: The Grapes of Wrath, Native Son, and For Whom the Bell Tolls. All three writers were involved with the Left at the time, and that commitment informed their fiction. Milton Cohen examines their motives for involvement with the Left; their novels' political themes; and why they separated from the Left after...