The American author who wrote the novel "The Grapes of Wrath" is John Steinbeck. This poignant tale portrays the struggles of the Okies during the Great Depression, emphasizing themes of injustice and resilience. Steinbeck's detailed narrative illustrates the hardships faced by migrant families in search of a better life in California, highlighting social issues still relevant today. His use of rich symbolism and vivid character portrayals makes the novel a defining work in American literature, celebrated for its emotional depth and social critique that resonates across generations.