After having a difficult time establishing a career as a novelist, O’Donnell discovered to his happy surprise that the reading public was very interested in his hobby of chasing ghosts, which he called “Superphysical Research.” After this, he made a habit of buttonholing friends and strangers to find out what experiences they had had with spirits and phantasms. He happily volunteered to camp out overnight in houses known to be haunted, and he made a concerted effort to discover any unhappy events that had, perhaps, led a ghost to inhabit. This, then, is a collection of his juiciest remembrances of running down ghosts in Europe and America, both in peace and in the horrors of World War.