For all the extraordinary advances in medical science seen in the past century, mental illness remains an area of conspicuous uncertainty. It’s perhaps a reflection of this doubt that three separate specialisms – neurology, psychiatry and psychology – contest overlapping areas of the field, and amid the confusion other disciplines such as philosophy and cultural theory have enjoyed an influence often unsupported by empirical evidence. It is in this disputed territory that Jonathan Rosen tells the heart-rending story of his friendship with Michael Laudor, a gifted young man whose rapid rise to the American intellectual summit is first cruelly restricted...