In the book, Jett Rink is a disrespectful field hand who has no redeeming qualities of which I'm aware, yet in the movie he has depth and pathos, and his downfall is understood as coming from his desire to do and be better without the support he needs to get there.
If you take both versions of Giant, the message is powerful. Quite a few grown men today remember without pause the author's name and the role she played in America's consciousness in the 1950s. In Giant, the movie, the ending is idealistic. Leslie changes Bick. He stands up for the Mexican and equal treatment and takes a beating in the process. The book is more realistic, though. Leslie argues for change but continues to look away. Her husband never changes but accepts it because he has no other choice. It is their children who embody the future and begin the social integration of Texas.
Click here to find out more about the book: Giant.