Hope is a major theme in this novel. The Joad family experiences trials and misfortunes on their journey, yet they learn that they are a part of a much larger family than they first realized-the human race.
Ma Joad and Tom Joad, in particular, learn this lesson. Ma Joad was more concerned with her own immediate family's well-being and unity at the beginning of the novel, but by the end, she has realizes that families must come together for the greater good.
Tom also comes to the realization that people must come together to fight injustice. Tom was more concerned with staying out of the public eye, and avoiding confrontation. But he also realizes that people must stand up for one another to accomplish feats that benefit society as a whole.