Not everyone believes in ghosts, but ghostly encounters have been reported, in all sincerity, all over the world and for 3000 years at least. However, though everybody knows what is meant by seeing a ghost, few are aware that they fall into several distinct types, and seemingly always have.;First there are revenants, returning voluntarily or under duress to the world of the living. When these are recently-dead family or friends, one might well suspect wish fulfillment. Occasionally, though, revenants appear to complete strangers. Next there are haunters who always appear in the same place and may be seen by many people over time, usually people who do not know them - but who sometimes identify them later. Then there are crisis apparitions who contact someone close to them at the moment of (usually) death. There are also phantasms of people who are still alive; their significance becomes plain only later when they turn up in physical form. Besides all these there are doppelgangers, who may warn or give advice, extra-terrestrials, poltergeists and others besides. None of them is at all like the strange ectoplasm that allegedly appears in human form at seances.;What is actually going on during a ghost encounter is a complete mystery, and one which Hilary Evans explores in this book. He takes as his starting point some 200 reports of paranormal experiences, each with its own strange implications, and examines them from the perspectives of science, psychical research, folklore and religion. He concludes that explanations which do not involve the supernatural are even less probable than those which do.