Consider the question. The Grapes of Wrath is an American realist novel written by John Steinbeck and published in 1939. The book won the National Book Award and Pulitzer Prize for fiction, and it was cited prominently when Steinbeck was awarded the Nobel Prize in 1962.

Who wrote the book the grapes of wrath?
 If the answer is 'John Steinbeck'; explain the reasoning:
The relevant information to answer the above question is: The Grapes of Wrath is an American realist novel written by John Steinbeck and published in 1939.