Commonality of Experience
The beauty of The Grapes of Wrath is that the experiences of the Joads speak for the experiences of thousands of other families traveling west in search of a better life. Such commonality of experience exists in the historical content that is laid out at the beginning of the novel, and also occurs within the novel's architecture itself. Steinbeck's novel transitions between chapters that detail the lives of the Joads and the chapters that deal with migrants more generally. It is in these chapters, which discuss broader currents and trends, that the commonality of experience truly shines through. These portions of the narrative are especially effective in communicating this theme because they always preface the more detailed, Joad-oriented chapters; in essence, they set the stage for the particular aspects of the Joads' lives. In this way, the commonality of experience adds gravity and importance to Steinbeck's The Grapes of Wrath, assuring it a place among great and resonant works of American literature.
Corporate Greed
Progressing hand-in-hand with the theme of industrialization, the idea of corporate greed is essential to the novel. This theme even ties in directly with the title: the phrase "grapes of wrath" can be found in both the Book of Revelation and the Battle Hymn of the Republic. Both of these references, as understood in Steinbeck's context, amount to a call for a higher power to right the wrongs that the corporate powers have done to the landless farmers. The greed of wealthy landowners is showcased from the beginning of the novel to the end -- they are ruthless and will do anything for higher profit margins.
This mentality is evident both in the general narrative chapters and in the chapters that deal specifically with the Joads and their direct acquaintances. At the hands of greedy landowners, people like the Joads lead pitiful and difficult lives. They are barely able to feed themselves on their daily wages, and the living conditions they face are horrible. Hundreds of thousands of people suffer just so a few corporate powers can make more money off another box of peaches or another pound of cotton. Under the pressure of these working conditions, the "grapes of wrath" of the laborers ferment and grow bitterly strong.
Industrialization
The heavy industrialization of American farming has enabled high-profile, wealthy landowners to extract greater profits from the land. These powerful landowners do not need to treat laborers well if they can opt to have efficient tractors plow the acres under their control. Along with industrialization, the creation of high-powered machines has enabled corporate interests to move laborers off the land and render them irrelevant.
Furthermore, industrialization has led to a farming and economic process that involves both vertical integration and horizontal integration. (Vertical integration occurs when the supply chain of a company is also owned by that company -- for example, the peach cannery also owns the farm where the peaches come from. Horizontal integration occurs when a company expands across an entire industry, acquiring several individual entities in a field of work. For example, this occurs when an especially powerful farmer is able to push fellow farmers out of business.) When both of these processes occur simultaneously, monopolies are able to grow and become very powerful.
Man's Connection to the Land
The farmer's, and man's, connection to the land is an important theme in The Grapes of Wrath. When the people of Oklahoma are forced to leave their land, this process proves to be devastating. These farmers have been a part of their land and have felt deeply connected to it for years: their hopes and dreams were lost or won in the soil, but now an inanimate tractor plows their onetime territory. The man who drives the tractor never touches the soil or interacts with it, which is a travesty according to the farmers. When the farmers leave, they lose part of themselves. But even beyond the difficulty of leaving their original land, the farmers are unable to create new connections with new land. They are forced to stay on the road, with no places to sleep or live, constantly moving. They are unable to put down roots, and such dislocation is particularly difficult considering their prior connections to set, customary ways of life.
Organized Labor
As the farmers become aware of the injustices that they continue to endure at the hands of the corporate powers, they also realize the futility of the actions of lone individuals. An individual farmer cannot even support his family and buy them food for dinner after a long day of work, and such a farmer's wages could continue to decrease at the whim of the landowners. (There is no incentive for the owners to provide a living wage when there is no organized resistance to their manner of operating.) If the workers can come together and communicate with one another, there is a possibility that they can stand up to the forces of corporate greed. If they do not stand together, they will continue to undercut one another and their wages will continue to fall. By organizing formally and by refusing to accept unfairly low wages, the laborers are able to exhibit their own form of power.
In the novel, organized workers are frequently called "reds" or Communists, but genuine labor organization (which often uses democratic structures and procedures) is a far cry from Communism.
Hope versus Hopelessness
As the Joads travel across the country, they remain unsure of what they will experience when they arrive in California. Each of the Joads deals with such uncertainty in a different way; however, regardless of whether they discuss the future or remain silent about it, there is an element of hope within all of the members of the family. They believe that they are starting out on a journey towards a new and better life. The men have hope that they will find work, Ma has hope that she will have a white house, and Rose of Sharon has hope that she will live in a town with an ice box and easy access to a movie theater.
The Joads maintain this sense of hope despite the fact that they inhabit a world that offers few reasons for optimism. Even as they face immense difficulties in their everyday lives -- work is not easy to find, food is expensive, and they are frequently forced to move from one place to another -- they maintain this positive outlook. When the men pull into the peach farm and begin to realize how difficult the work will be, Ma still believes that soon the Joads will save enough money to buy a house with some land. Their attitudes contrast with their environment, thus creating a tension between hope and hopelessness that emerges at different points throughout the novel.
Death and Suffering
Related to the theme of hope and hopelessness, the theme of death and suffering is essential to the difficult environment that the Joads face. Death is prevalent from the very beginning of the novel until the very end. Grampa dies on the first night of the trip, and Granma dies just as the Joads enter California. Even for the Joads who are relatively healthy, unpleasant conditions still abound. They cannot escape the elements and are barely able to eat. Rose of Sharon, who is pregnant, is unable to get the nutrients she needs for her baby, and her suffering is exacerbated by the journey as well.
Ultimately, the suffering of the Joads reflects the suffering of thousands of families traveling to California and looking for work. The bleak environment has been created by a variety of factors, the most prominent which are corporate greed and the industrialization of agriculture. Yet despite the prevalence of death and suffering, the Joads and many of the other traveling families try to maintain hope; they keep alive their belief in the American Dream and reassure themselves that a better life awaits them.
