Who is Joe Bastianich from Heat: An Amateur's Adventures as Kitchen Slave, Line Cook, Pasta Maker, and Apprentice to a Dante-quoting Butcher in T and what is their importance?

Joe Bastianich became Mario Batali's partner after his partnership with Steve Crane desolved. Joe and Batali opened Babbo together with Batali running the kitchen and Joe running the kitchen. Eventually Joe and Batali opened three more restaurants together and a restaurant for their friend, Andy.