While speaking at a memorial event for her father, the novelist Siri Hustvedt suffered a violent seizure from the neck down. Was it triggered by nerves, emotion - or something else entirely? In this profoundly thought-provoking and revealing book, Hustvedt takes the reader on her journey through psychiatry, philosophy, neuroscience and medical history in search of a diagnosis. Conveying the often frightening mysteries of illness, she illuminates the perenially mysterious connection between mind and body and what we mean by 'I'.