I know. All of the previous comments told you all. But I want to say something of my own.<br /><br />This great thriller will live longer indeed. For a lot of reasons. The one I want to talk about here is the strong focusing on the characterization firstly in this script. Because this is something really rare in any of the American thrillers nowadays.<br /><br />Here you have 2 points of view come from 2 different generations or simply 2 kinds of human beings.<br /><br />The first is (David Mills/Brad Pitt) who is so rash, tense, running mostly after his sensations and always relies on the photos, the shape of things. But despite his true zeal, courage, and idealism he is so unwise and very impetuous who could easily hurt or lose himself. He is too weak to wait justice, so he goes and gets it by his hand because he is a slave for his excitability.. his emotionality.<br /><br />The other one (William Somerset/Morgan Freeman) is an earlier generation who had all the goodness and rationality. Being so discreet, relies on the books, and a real cold proficient expert. This one is not perfect also ! He is too enfeeble to stand love or its pain, responsibilities, or even its loss. So there is no joyful thing about his life nor lasting thing in his life ! <br /><br />Both of them make together one hell of a perfect unit (so they succeed in pursuit the killer). But HEY, it's not (lethal weapon) here. So you'll have them both at variance, too contradictory and the only clear medial between them was the first's wife. Therefore when she died (and Brad Pitt went and killed the killer) the borderline already ended and there is no medial no more ! So separation became the fate.<br /><br />They are two very irreconcilable ways, or persons, or feelings : the love which kills the fear (so Brad Pitt lost his life), and the love which is killed by fear (so Morgan Freeman is losing his own)!! And as for (John Doe/Kevin Spacey) the limit is pushed in the extreme; so he had his fear or his love or maybe both killed too long ago. He was despising the extremism of the human lusts because he wasn't one. He lost his humanity completely. Therefore he became a killing machine, a loose madness, or the extremism itself.<br /><br />Balance between your love and your fear or you'll be the killer and the victim ! That's one premise which will make this film live for so many upcoming generations.