The main photographers were Russell Lee, Marion Post Wolcott, Jack Delano, Walker Evans and Dorothea Lange. They were all employed by Roy Stryker who ran the Information Department of the Farm Security Administration. Stryker used photography to garner support for the F.D. Roosevelt's New Deal.
A brief curatorial essay sets the scene. Marion Post Wolcott joined Stryker because
“I had deep sympathy for the under-privileged,resented evidence of conspicuous consumption,(and) felt the need to contribute to a more equitablesociety.“Get yourself along to the exhibition. You are probably used to seeing the black and white images but (as the Photographer's Gallery site says) the colour ones give it a "shocking immediacy and freshness bringing to life the human cost of the Depression" .
If you want to see some of the images go to the Library of Congress, browse the Geographic Location Index for New Mexico, Pie Town. I'm unsure of the persistence of this link to New Mexico, Pie Town but here it is.