Robert Caro, Pulitzer Prize-winning biographer of President Johnson delivers the keynote address in the Kennedy Library's ongoing examination of 20th century presidents. He is joined by Jack Valenti, who served as Special Advisor to President Johnson; Pulitzer Prize-winning New York Times writer Anthony Lewis; and Boston University historian Bruce Schulman to discuss President Lyndon Baines Johnson's legacy. Harvard University historian Lizabeth Cohen moderates the discussion.