Tom Joad is a great example of a dynamic character. A dynamic character changes in a significant way over the course of a story. Tom starts out as cynical person who doesn't think much about others, but by the end he is part of a movement to improve the lives of the workers who were so victimized by the Great Depression and the Dust Bowl.
Enotes can be useful for this kind of thing, if you don't get what you are looking for in the discussion. For most books, there are notes on specific characters. There is not going to be as much information here about this one character because of how many characters there are. Here's the character description:
There is much given to us about Tom Joad in the course of Steinbeck's work. As he is the central character, it is through his own eyes that we learn as to the condition of life during the Dust Bowl and how the Joad family absorbs this life. Tom is someone that starts off as very much driven by isolation and self- interest. His experiences while incarcerated cause him much in the way of numbness and a desire to not be involved with people. His killing a man in self- defense and the time spent in jail have isolated him emotionally from others. Yet, Tom is someone that cannot keep his eyes closed to what is happening to poor people at the hands of the rich and at the hands of each others. It is here where Tom experiences growth and maturation through his work with Jim Casy. In the end, Tom learns that there is a universality that links all human beings despite the challenges of the present condition. It is in this realization, in this love for humanity, that forces him to leave the family in pursuit of a higher goal. Tom represents the search for meaning as someone who lacked it to someone who now fully understands it. Through Tom, Steinbeck is making a bold assertion in arguing that human beings are not victims or automatons of their existing social conditions, and that they can be agents of transformation in making reality as it shoul dbe as opposed to how it is.
What I mean is what describes him, what he like, hate, who he's related to. Stuff like that.