With his golden boy good looks, on-screen charisma, environmental convictions and commitment to supporting independent film, Robert Redford was a giant of Hollywood. As tributes pour in following his death at 89 years old, film critic Emma Jones and Redford's biographer Michael Feeney Callan reflect on his starring roles, his on-screen chemistry with legendary actresses and the strong convictions that saw him launch the Sundance Film Festival and, in doing so, change the face of contemporary American cinema.