People called it the Dust Bowl, an environmental disaster that struck the Great Plains in the late 1930s, when the country was already reeling under the Depression. John Steinbeck's best-selling novel, The Grapes of Wrath, profiled some of the hardest hit: tenant farmers forced off their land and into migrant labor far from home. When the movie version was announced, people worried that Hollywood would ruin it. They didn't need to. It was directed by John Ford.