John Steinbeck was an American author who wrote many novels, including 'The Grapes of Wrath' and 'Of Mice and Men'. His works often featured characters from the working class, and four of his most famous characters are Okie, Aron, Cal, and Joad. Okie is a migrant worker from Oklahoma who moves to California in search of work. Aron is the son of Tom and Ma Joad, and he is the one who leaves the family to pursue his own dreams. Cal is a character who is a foil to Tom Joad, as he is a successful businessman who has made money off of the suffering of others. Joad is the protagonist of 'The Grapes of Wrath' and is the leader of the Joad family. Finally, Lennie is a mentally disabled man who is George's companion in 'Of Mice and Men'. All of these characters are integral to Steinbeck's works and represent the struggles of the working class.