What is the theme in Tobacco Road by Erskine Caldwell?

Inability to adjust is a central theme in the book.The Lesters live on a piece of land that belongs to another man. They are sharecroppers, people who work the land for another person in exchange for a place to live. However, the man who owns the Lesters' home has given up on farming and moved to the city. This man has allowed the Lesters to remain on the land but has refused to make any repairs to the home or to offer the Lesters any financial assistance in order to work the land. This leaves the Lesters with land all around them but no means to get the money to buy seed and fertilizer. They have a home, but the home is falling apart around them and they also have no means by which to make repairs. The family also does not have money to buy food.