Mention "the supernatural" to most people and they immediately think of ghosts. A ghost is popularly considered an apparition, generally of a dead person but sometimes of an animal. Such an apparition may come to warn the living of impending trouble or (if the deceased died vowing revenge) to haunt them.
 

Ghosts usually seem to be tied to the places in which their beings lived and suffered — it is rare for there to be no apparent connection between a place and an attendant apparition — and to be universally unhappy. Indeed, so rare is contentment in the world of apparitions that to speak of a happy ghost seems a contradiction in terms.
 

Ghosts have been recorded from the earliest times: Greek and Roman literature, in particular, are full of them, and innumerable instances of their appearance have been recorded up to the present day. Neither religion nor rationalism has managed to damage the general assumption that some places can be haunted, either by particular ghosts or simply by an atmosphere which somehow places them apart from other, happier places.
 

There are many different kinds of ghosts and few rules that can be applied to their appearances. Beyond an occasional lowering of the temperature, they do not seem to affect the environment much — for example, lights do not brighten or dim — and they can be seen in bright sunlight or in dark shadow. Occasionally, the figures seem to have some inner illumination.
 

The ghost is seen obliquely — for example, out of the corner of the eye; indeed, some people claim that one can never look directly at a ghost. Nevertheless, there are many records of conversations purported to have been held with apparitions. Sometimes, more than one person has seen the same ghost; occasionally observers claim to have actually touched ghosts, or have made physical contact with a human being who, it has later been proved, could not actually have been there.

Many ghosts have the reputation of appearing again and again in the same environment — for example, houses in which their living counterparts have died. In such cases they usually seem to haunt one room, typically the one in which they were murdered; but sometimes they will move from room to room.
 

We usually speak of "seeing" a ghost, yet there have been reliable reports of people merely sensing a presence in the room with them, and of having been able to describe it without actually observing it. Perhaps the best-known example is of a woman who awoke one night in a room at the Chateau de Prangins, near Nyon in Switzerland, and was convinced that a man was sitting writing at a desk in the room, dressed in a long, flowered dressing-gown. She described him vividly to her husband; but when she was persuaded to look directly at the desk, could see no-one there. Next morning she was told she had described the figure of Voltaire, who often used the room during his lifetime and was regularly seen there.
 

Some people, of course, go out of their way to seek out ghosts. However, to most people they appear unannounced and unexpected, often "out of thin air." They simply look up and there is the apparition standing before them. Most ghosts seem to disappear right under the eye of the beholder, sometimes gradually fading away, sometimes simply vanishing if the observer makes a sudden movement, switches on a light, tries to touch the ghost or speak to it. It is a cliché that ghosts have the ability to walk through walls or closed doors, but there are many reports of those who seem to have done so.
 

The transparent ghost is another cliché; but most ghosts appear solid enough to cast shadows, although very occasionally transparent apparitions are reported to have been seen, or ghosts have gradually seemed to become transparent as they disappear. The idea of the headless ghost is not well supported, although sometimes only a head, or a pair of hands, has been seen, apparently suspended in mid-air. Among the strangest of ghosts is the 'doppelgänger,' or ghost of oneself, whose appearance is thought always to precede death.

It is a mistake to suppose that all ghosts are of people. There is a well-known case of a ghostly bus which was said to run on a London route (see Phantom Bus). The ghost of a bombed house has been seen, standing on the site it once occupied. Ghostly clothing, letters, money, even machinery has appeared. Ghostly animals have sometimes been seen — or heard, without any human apparitions. Interestingly, ghost cats seem almost always to appear alone, while ghost dogs more usually appear in ghostly human company (a reflection of living canine and feline characteristics, perhaps).
 

In the search for rational explanations, it is fair to concentrate on the physical state, as well as the state of mind, of the person concerned. Ghosts seen from bed, during the night, or just upon awakening — and a good many of these have been recorded — must be suspected of being part of a dream. Those encountered in broad daylight are another matter. Some have appeared to people under much the same conditions as poltergeists — that is, when the observers have clearly been awake and unaffected by exhaustion or mental instability.
 

The fact that most people merely see ghosts (one researcher records that of the people who see ghosts, 84 percent only see them, while 37 percent hear them and 15 percent touch them) must suggest at least the possibility of hallucination. A relatively few people also have other senses affected: a few record that they feel a drop of temperature in the presence of a ghost, and even fewer suggest that ghosts are accompanied by a curious smell.

It is extremely difficult to produce any generally acceptable proof of the appearance of a ghost. Even if two or three people see the same apparition, there is the possibility of group illusion; while the very circumstances under which apparitions usually appear preclude careful scientific observation — ghosts are notorious for their failure to appear under test conditions (no good reason for claiming they do not exist, but a hindrance to proving that they do). The most famous ghost-hunter, the Englishman Harry Price (1881-1948), had no real success at proving the existence of ghosts, but he witnessed, and recorded many strange experiences, especially at Borley Rectory.
 

Occasionally people have claimed that ghosts have told them things that they could not know, have uttered warnings or provided information about the future. Very few of these are any more reliable, as proof, than simple anecdotes. The case for ghosts, although sometimes extremely interesting, must be regarded as unproved.
 

Related online classes and learning: -- Understanding Parapsychology and the Paranormal A look at the components of the fascinating world of parapsychology and the paranormal. Is there more to the human condition than merely blood, skin , bone and nerves? Find out as we explore reincarnation & past lives, channeling, dreams, out of body experiences, astral travel, numerology, automatic writing, meditation and visualization, auras, colors, crystals, dowsing, energy healing and much, much more. Click HERE to enroll. Also available: -- Reincarnation East and West We will explore the phenomenon of reincarnation from the perspectives of Eastern religious and spiritual teachings, and modern Western investigations (scientific and otherwise). Cases of people who have had reincarnation-related experiences will be examined. As the course moves forward, we will also explore the deeper implications of reincarnation for the individual and society. On a voluntary basis the student will complete an exercise (not using hypnosis) which, using a series of questions, is design to reveal patterns about our own past lives. Other class assignments will introduce the student to researchers and people who have had reincarnation experiences. Click HERE to enroll. Instructor Stephen Sakellarios -- How To View And Interpret Auras This course will enable you to view your own aura and the auras of others. You will discover several different techniques that work best, even if you have never done anything like aura viewing before. You will also learn the meaning behind the many different colors and patterns that can be seen in the human aura. And, when imbalances are discovered, you will learn what you can do in order to repair and enhance the aura. Click HERE to enroll. -- For more new age and alternative beliefs online classes, click HERE.

Recommended videos:   Unsolved Mysteries: Ghosts - DVD Buy this DVD Ghosts of England & Belgrave Hall - DVD Buy this DVD Real Ghost Stories Collectors DVD Set Buy this DVD Set Ghosts of California - DVD Buy this DVD Hollywood Ghosts and Gravesites - DVD Buy this DVD Ghosts & Witches of Olde England - DVD Buy this DVD Unexplained - Hauntings (A&E DVD Archives) - DVD Buy this DVD Unsolved Mysteries: Psychics - 4 Disc DVD Set Buy this DVD Set From Beyond: Werewolves & Apparitions Buy this Video Other related video titles: -- Astrology & Seance. -- Castle Ghosts of England. -- English Ghosts. -- English Ghosts/Hollywood Hauntings. -- From Beyond: Ghosts. -- From Beyond: Ghost, Poltergeists Demons & Spirits. -- Ghosts & Phantoms/Witches & Demons. -- Ghosts & Witches of Olde England. -- Ghosts of California. -- Ghosts of England & Belgrave Hall. -- Ghost Stories. -- Hollywood Ghosts and Gravesites. -- Houdini - The Great Escape. -- Houdini: The Life of the World's Greatest Escapologist. -- Houdini: Unlocking His Secrets. -- Mysteries & Myths of the Twentieth Century: 20th Century Ghosts/Madonna. -- Real Ghost Stories Collectors DVD Set. -- Secrets of the Unknown - Hollywood Haunting. -- Secrets of the Unknown - Poltergeists. -- Strictly Supernatural - Seance. -- The Unexplained: Poltergeist. -- UFO's and Channeling. -- Unsolved Mysteries: Ghosts - DVD. -- Vampires & Ghosts. -- Werewolves & Apparitions. -- World of Spirits. -- Click HERE for more related videos. -- Click HERE for related magazines. Recommended software: Full-Color Angels CD-ROM Heavenly images, angels and cherubs Buy this CD-ROM & Book Set The URANTIA Book - CD-ROM The History of Earth Buy this CD-ROM Breaking the Rosetta Stone Code CD-ROM Buy this CD-ROM -- Click HERE for more related software. Recommended art prints and posters: The Ghost of Banquo Chasseriau, Theodore Buy this Giclee Print The Ghost Story Smallfield, Frederick Buy this Giclee Print Telling Ghost Stories Buy this Note Card -- Click HERE for more related art prints and posters. Recommended books: Hello from Heaven: A New Field of Research-After-Death Communication Confirms That Life and Love Are Eternal Buy this Book Afterlife Encounters: Ordinary People, Extraordinary Experiences Buy this Book Spook: Science Tackles the Afterlife Buy this Book Other related titles: -- 500 British Ghosts and Hauntings. -- Angels and Apparitions: True Ghost Stories from the South. -- Apparitions and Survival of Death. -- Apparitions: Mystic Phenomena and What They Mean. -- Banshees, Bugles and Belles: True Ghost Stories of Georgia. -- Chicago Haunts: Ghostly Lore of the Windy City. -- Classic American Ghost Stories: 200 Years of Ghost Lore from the Great Plains, New England, the South, and the Pacific Northwest. -- Coastal Ghosts: Haunted Places from Wilmington North Carolina to Savannah Georgia. -- Ghostly American Places. -- Ghosts and Haunts from the Appalachian Foothills: Stories and Legends. -- Ghosts, Hauntings and Possessions: The Best of Hans Holzer, Book 1 (Fate Presents). -- Ghosts of Gettysburg: Spirits, Apparitions and Haunted Places of the Battlefield. -- Ghosts of New England; Spine Tingling Encounters with the Phantoms of New England. -- Hans Holzer's Travel Guide to Haunted Houses. -- Haunt Hunter's Guide to Florida. -- Haunted America. -- Haunted Heartland. -- Haunted Hotels: A Guide to American and Canadian Inns and Their Ghosts. -- Haunted Places: The National Directory - Ghostly Abodes, Sacred Sites, Ufo Landings, and Other Supernatural Locations. -- Haunted Wisconsin. -- Historic Haunted America. -- I Never Believed in Ghosts Until...: 100 Real-Life Encounters. -- Phantoms of the Rich and Famous. -- Riders in the Sky: The Ghosts and Legends of Philmont Scout Ranch. -- The 25 Scariest Hauntings in the World. -- The Field Guide to North American Hauntings: Everything You Need to Know About Encountering over 100 Ghosts, Phantoms, and Spectral Entities. -- The Ghosthunter's Guide: To Haunted Landmarks, Parks, Churches, and Other Public Places. -- The Great Apparitions of Mary: An Examination of the Twenty-Two Supranormal Appearances. -- The Haunting of Cassie Palmer. -- Click HERE for more related books.

Further info:
Ghosts & Hauntings.
International Society for Paranormal Research.
Philadelphia Ghost Hunters Alliance.
Spiritual Investigations UK.
The Apparitions of the Virgin Mary in the 20th Century.
The GhostWatcher.