Few movies have caught and shocked our imagination as the Alien cinematic quartet and the odyssey of Sigourney Weaver's Flight Lieutenant Ellen Ripley. In this book, Stephen Mulhall goes to the Alien films themselves and shows them to be fascinating examples of philosophy in action. Bringing a philosopher's eye to film, he reflects on what the Alien films tell us about the relation of human identity to body, explores the nature of sexual difference, and asks what logic, if any, operates within the apparently Darwinian universe the alien beings inhabit. On a deeper level, he argues that the films command our attention via their skilful opposition of religion and nihilism, of the natural with the technological.