He is the youngest of all the ranch men. We don't know much about him, but we know that he didnt have a good childhood. We know this because he reads a lot of childs comics which he still treasures. this implys that he is still childish. However he tries to act like a man by going to the whore house and playing cards with the other men.
He is the ranch owner, he is described as being stumpy and short tempered. Curley is his son and Curley's wife is his daughter in law. The Boss isn't seen very much in the novel so there isn't much to say.
He is a 'Thick bodied' ranch hand. He is responsibe for killing Candy's dog with little sympathy to show.