Grapes of Wrath focuses on both the situation of migrant workers during the Dust Bowl as a whole, as well as the situation of a single family during the event, the Joads. Each chapter fluctuates between either the macro view or the micro view. One chapter will be devoted to the workers, the next to something that will affect the Joads. The intercalary chapters, or the chapters containing a macro view, are used in the novel as three main functions: to provide a recurring basis for the novel's themes, to give the reader an insight to the society's background at that time, and to provide a historical account of the "disaster.".
Chapter twelve provides the reader with an insight into the society's background. The migrants are portrayed as unknowing and exploitable, as seen in their purchases of vehicles in poor condition at prices that are highly inflated. The salesmen cheat the farmers, as the farmers were cheated from their farms and will be cheated from the promise of a job in California. They have no other skill and little education, and their only fallback is California. The reader is presented with the grave situation these people are in; these farmers must either farm or die.
Through Mae's story in chapter fifteen, the reader is able to see characters behaving in correspondence with the specific theme of kindness. Mae, a waitress in a side road diner, refuses a migrant worker and his son, not knowing their situation. She then decides to sell the two foods and candy at a lesser price. Through the truckers who were also at the diner, she learns of the man and boy's situation and that what she did really was an act of kindness. In return for her deeds towards the man and boy, the truckers give her an extra amount of pay so as not to lose company money. The theme of kindness presents itself twice, in tw0o different forms in this chapter.
The historical account of the era is exemplified in chapter seventeen.
