Steinbeck's The Grapes of Wrath is an epic novel written in the third person that depicts an Oklahoma family struggling against nature and society to survive.
As such, it is a work of naturalism, or a naturalistic work, featuring humans as victims of natural and societal forces. The Joad family members are victims, but they are not passive, as is sometimes the case in naturalistic fiction. Their struggle is epic, even though, perhaps, impossible to win. They do manage to maintain hope, however, and are still struggling at the close of the novel.
It is a work about the Great Depression, The Dust Bowl, and migratory laborers.
One thing the novel does not do, however, is reveal a full study of the issues involved. It presents the issues and themes from only the point of view of the victims.
John Steinbeck's novel The Grapes of Wrath is a book about the "Oakies" who went to California following the depletion of the grasses and the resulting dust bowl in Okalahoma. The Joads are a family who have stuck together and tried to survive like so many other poor farm families from Okalahoma did. However, the winds blew away all chances of their survival and resources. Like many others, they bought an old vehicle and headed west to California with dreams of a better life.
Once they neared California they began to experience the prejudice of the people against them. They were not wanted, were called ignorant and vermin, and were told to turn back. The most comfort they found in California was when they were encamped in an immigrant camp for migrant workers. It is there that they can experience some comradeship with others.
The dynamics of the migrant workers and the locals in the Salinas Valley led to problems that the Joads had not anticipated. Steinbeck wrote the novel as a political statement about the conditions and the treatment of the migrant workers.