 In the film, Denethor panics at the sight of Sauron's army, prompting Gandalf to knock him out with his staff and take command, whereas in the book Denethor states that it is senseless to run from the enemy as there is no hope of escape.In the book but not the film, Denethor uses a "palantír" for knowledge of the Enemy, but Sauron weakens him through it.The film, lacking the palantír as an explanation of the change in Denethor, attributes his madness to grief over Boromir.