A beautiful piece of literature in which Ian McEwan explores the idea of rationality and what constitutes proof of reality. He does this by developing two characters: a rational science writer and an extreme ideological religious believer and proceedes to crash them into each other by means of a fatal accident. After the accident Jed, the devout Christian, is convinced that level-headed Joe has fallen in love with him. Jed has discovered that his life is contingent on Joe's for any meaning. Jed's love becomes obsessive; this is paralelled by Joe's obsessive re-examination of his own life. Joe remains calm although as he continues his re-examination he discovers that many ideas he has previously been able to explain through science become less black and white. Gradually everything he was sure of becomes questionable until his rational mind starts to be contaminated by questions.