During the Great Depression, these photographers documented the plight of poor farmers. Dorothea Lange may have produced the single most enduring image among them, a portrait of Florence Owens Thompson staring worriedly into the middle distance as two of her children bury their faces in her neck, called Migrant Mother. Walker Evans, another FSA photographer, collaborated with writer James Agee on a study of three sharecropping families in Alabama, called Let Us Now Praise Famous Men. Gordon Parks, whose photo of an FSA cleaning woman was both posed and titled in ironic homage to Grant Wood's American Gothic, was a pioneering African-American photographer who later directed the film Shaft.