Who is jack Duane? What does jurgis think of him?

Jack Duane is an educated man who has seen much of the world. He is a professional safecracker, though he is in jail for being a public nuisance. His arrest had been because the police could gather no evidence against him for safe-cracking crimes

For Jurgis, Duane represents adventure. He listens with wonder to Duane’s stories “of midnight ventures and perilous escapes, of feastings and orgies, of fortunes squandered in a night.” Jurgis finds it pleasant to talk with such a man and Duane introduces him to all the other prisoners whom he knows by name.