Late one evening the telephone rings, and on the line is a stranger. They tell you that your nine-year-old son gave them your number. Your heart stops. You tell them that your son has been dead for almost 20 years. They know this, they say. He wants you to come and see him.What do you do when reality begins to fray around you? Where do you go when science cannot explain your experiences? The Society for Psychical Research was founded in 1882 to tackle these very questions and to shine light on the shadowy world of the supernatural. Distinguished members have included prime ministers and Nobel Prize-winning scientists.But the most prolific of all the SPR's paranormal investigators was a young British naval officer named Tony Cornell. A rationalist and a sceptic he became haunted by a wartime encounter in India that changed everything . Between 1950 and 2010 he became perhaps the world's most prolific investigator of psychic phenomena and paranormal events. Alongside his colleague, the psychologist Alan Gauld, they combined the roles of detectives, exorcists and psychiatrists, returning time and again to the unsettling spaces that exist on the very periphery of our tidy, rational lives: Ghosts. Poltergeists. Psychic powers.Drawing on a previously untapped archive of Cornell's case files, which survive as a unique repository of encounters reported by ordinary people, Chasing the Dark is the compelling story of our relationship with the supernatural. What do these atmospheric and often chilling cases teach us about who we are, and the anxieties that consume us? And why do the dead still find ways to make themselves known?