Good guess! But...
John Steinbeck (1902-1968) did not work for the Federal Writers' Project. However, he was employed by the WPA for a time as a census-taker. He took a census of dogs in California's Monterey Peninsula area.
The inspiration for The Grapes of Wrath came from a series of articles that Steinbeck was asked to write in 1936 for the San Francisco Chronicle. His subject was the migrant farm workers who had fled to California to escape the "Dust Bowl."
For images of the Dust Bowl, visit the New Deal Library.
Monarch Notes for Windows, Parsippany, NJ: Bureau of Electronic Publishing, Inc., 1993.
Maitland A. Edey (Ed.), This Fabulous Century: 1930-40, New York, NY: Time-Life Books, 1969.