Central to The Grapes of Wrath is a single lie: thousands of families move west to California because they believe it to be the land of plenty, a place full of jobs and opportunity. This lie is spread through a yellow pamphlet dispensed by a Californian landowner looking for workers, and it both gives families a sense of hope and strips them of hope. Several entities help to sustain this lie: the banks, the car salesmen, the merchants, and the landowners. The Joads are deceived into thinking that their worries will be forgotten once they get to California.
The lie of jobs in California gives the Joads hope, allows them to survive.
Hardly anyone tells the truth outside the world of the Joad family.