"In the film, Denethor refuses to light the beacons to summon Rohan, and Gandalf has Pippin light the first beacon, whereas in the book Denethor had lit the beacons before Gandalf's arrival.The films have Denethor send his remaining son Faramir on a suicide mission to Osgiliath, whereas in the book Denethor's cavalry rescue Faramir.