At twenty-one, John Nash was a brilliant and highly eccentric mathematician at Princeton University when he invented game theory—the most influential theory of rational human behaviour of our time. At thirty-one, at the peak of a brilliant career, Nash was diagnosed with schizophrenia. Beset by bizarre delusions and repeatedly incarcerated in mental hospitals, Nash spent most of the next three decades as a silent, ghost-like figure haunting the Princeton campus. At sixty he was all but forgotten, when twin miracles—an almost unprecedented remission of schizophrenia and a decision by the Nobel Prize Committee to honour his great achievement—restored the world to him.