When Steinbeck was prepare the corrections of the of Mice and Men, he was planning his next book, The Grapes of Wrath. His first journalistic assignment in the fall of 1936 make him want to write the book. The liberal San Francisco News sent Steinbeck to cover the migrant situation in California; he went to the Arvin Encampment in Bakersfield, California to talk to Tom Collins, manager of one of the first of the government camps set up in California to alleviate housing problems for Southwest migrants pouring into the state from the Dust Bowl regions.Steinbeck interviewed Collins and migrants, and studied the situation first hand, after which he wrote a series of articles on the migrants plight, published as The Harvest Gypsies.By December 1936 Steinbeck thought that his next big book would be tell a migrant story. Although Steinbeck felt difficult to write The Grapes of Wrath, but he want to cry out for the poor, then The Grapes of Wrath come out.    
    Whenever the Great Depression(1929-1939) is mentioned, people can not help referring to Steinbeck, because Steinbeck is always regarded as the most representative writers in that period. The whole 30s is the unbearable years in American history, and The Grapes of Wrath is the representative fiction of that period. As we know, economic crisis always happened in America. But none of them can compare with the crisis of 1930s.
    The Great Depression shake American economy, causing innumerous unemployment and bankrupts, changing the economic system of Americans. It is the first time that Americans faced extreme poverty on a large scale because of circumstances beyond any inpidual’s control. The economic structure of America altered, as large farms replaced small ones and the financial picture enlarged to include corporations, large investments and amassing fortunes. 《愤怒的葡萄》中汤姆的转变(2):http://www.youerw.com/yingyu/lunwen_6496.html