At the age of 21, a brilliant and highly eccentric graduate student made a major contribution to game theory: John Nash had discovered an influential theory of rational human behaviour. But ten years later, at the peak of a dazzling mathematical career and soon after his marriage to a physicist, Nash suffered a breakdown. Diagnosed a schizophrenic, he was beset by bizarre delusions, unable to work, and repeatedly incarcerated in mental hospitals. He spent most of the next three decades as a silent, ghost-like figure haunting the Princeton campus. Then, when he was 61 and all but forgotten, a dramatic remission of his illness and the Nobel Prize committee's decision to honour his achievements restored the world to him. His story is told in this book by an author who is intimately familiar with the academic world that Nash has occupied. She wrote it with the backing of Princeton and Nash's friends and colleagues.