There's little debate that Robert De Niro is one of the greatest screen actors of his generation, perhaps of all time. His work, particularly in the first 20 years of his career, is unparalleled. De Niro become known for his deep involvement in his characters, resulting in extraordinary, chameleonic performances. Yet little is known about the off-screen De Niro--he is an intensely private man, whose rare public appearances are often marked by palpable...