Which historical events most shaped works by John Steinbeck?

The Great Depression and its impact on society greatly influenced John Steinbeck's works, notably "The Grapes of Wrath" which focuses on the struggles of Dust Bowl migrants. Additionally, Steinbeck's experiences working alongside migrant farmworkers in California informed his depiction of the hardships faced by laborers in works like "Of Mice and Men" and "In Dubious Battle."