What explains sightings of ghosts? Why do they fascinate us? And what scientific proof is there? Taking us through the key hauntings that have obsessed the world, from the true events that inspired Henry James's The Turn of the Screw up to the present day, Roger Clarke unfolds a story of class conflict, charlatans, and true believers, with a cast that includes Samuel Johnson, John Wesley, Harry Houdini, and Adolf Hitler.