What is shadow, what is light? asks Dr. George, a Vancouver, B.C., psychologist, echoing Plato's parable. Certainly what we consider to be "real", "out there", is not as self-evident as at first appears.

"The framework of ordinary reality is made of our assumptions and expectations, our desires and fears. The angry dwell in a world of enemies; the ambitious, in a world of opportunities; the consumer, in a world of commodities. These are not just 'attitudes' -- they actually determine, to a large extent, our very perceptions," writes Dr. George.

Even our awareness of our own bodies is a mental construct, the author claims. As for memory, that, too, is not what it seems. "The image we summon from the vault of memory is more like an oil painting of the bygone event than like a photograph."

What most strongly colours our view of "reality" is our world view. This is our set of beliefs which infuse everything we do or think and which we inherit first from our parents and secondly, from the society around us.

Dr. George writes, "The foundations of belief about cosmos, society, body and self are laid even before we fully learn to speak. Throughout life, these primordial convictions will remain impossible to express -- and therefore impossible to question."

Of course, the irony is that, if Dr. George is correct, then his postulates are also part of one world view among many!

Whatever our world view may be, and wherever it may come from, it rapidly takes on an "aura of absolute reality."

And thus it is extraordinarily difficult to change someone's world view. The author draws upon the work of Jean Piaget to explain how we keep our world view intact. We either assimilate or we accommodate challenges to our sets of beliefs. That is, we either keep our world view unchanged by fitting the new information into it, or we change the world view just enough to adapt to the challenge.

Dr. George adds that we may do neither. We may simply ignore the new information. (Shades of bigots and zealots!) The third option is strongly influenced by what others around us are saying.

This brings us to what the book is about. And that is, experiences which, though statistically common, do not fit the prevailing world view of the "modern West [which] is primarily defined by science."

As the author writes, science "does not have a place for encounters with spirits, for souls that leave the body or reincarnate or for mental powers that are not subject to the limitations of the body's muscles and senses. The mainstream world view could accommodate visitors from other planets, provided they got here via technology rather than magic; and even strange creatures living in lakes or forests would be acceptable, if they turned out to be biological entities of some sort. But even these possibilities are not currently accepted, for lack of convincing evidence."

Unusual events (i.e. experiences which challenge one's world view) come either from the outside (weird happenings) or the inside (a mind that itself functions in an unusual manner).

Here is a summary of Dr. George's outside and inside effects:

a) External influences

* Social cues from other people (who are also, e.g., seeing a ghost);

* Impaired sensory input (e.g., dim light, drums, flashing lights);

* Electromagnetic conditions (e.g., thunderstorms or quartz deposits);

* Uncommon natural events (e.g., hordes of parachute spiders);

* Meeting "an actual discarnate spirit or Sasquatch or UFO occupant, if indeed there are such things."

b) Internal influences

"Most supranormal phenomena are experienced by people who are neither mentally nor neurologically disordered in any obvious way." They often stay silent, writes Dr. George, to avoid the risk of having their honesty or their sanity questioned.

Explanations for supranormal events fall into three categories:

* Conventionalist -- there's some prosaic reason;

* Extentionalist -- adds to the science world view with such propositions as powerful spirits or transcendent faculties.

* Anomalist -- this outlook says that paranormal theories are inadequate, but that the conventionalist perspective doesn't explain everything, either.

The dictionary-format of the book makes it easy to look up whatever paranormal, mystical or transcendental experience interests the reader. I was disappointed there was no entry for "crop circles".

Let's look at two entries chosen at random.

Olfactory hallucinations

"A false perception of smell. Olfactory hallucinations can feature in epilepsy and schizophrenia, but are most often reported by sufferers of hysteria. Mysterious odors are sometimes sensed in the hypnagogic state. See also odors of sanctity, poltergeist."

Out-of-body experience

Four pages on OBEs tell us that anywhere from 8 to 15% of the general population report such an experience. "Among subpopulations such as college students, it is much higher, up to 48%, in some samples." Normal people as well as the mentally disturbed have OBEs, and reports date back thousands of years. Even St Paul seems to refer to an OBE [Corinthians 12:2].

Waves of interest in OBEs have swept through society, such as during the time of the Gnostics [early A.D.] and the Middle Ages. Witches in the Renaissance and Reformation were commonly thought to easily be able to travel outside their bodies. Such beliefs waned until revived in the middle 1800s when Spiritualism and Theosophy gained many followers.

Science began to take an interest and had to quickly drop the accusation that an OBE was an hallucination, a sign of mental illness. Research during the last 25 years has examined OBEs in a number of ways. Dr. George describes the typical experience of people who spontaneously undergo an OBE and notes that they appear "quite vivid and realistic, without the shifting, blurred nature of dreams."

About 15% of OBE experients claimed that they learned things about distant places which they "could not have obtained if their senses had been restricted to the immediate vicinity of the physical body." Experiments to investigate these claims have so far been inconclusive.

Are there differences between OBE experients and people who have not had such an experience? Not in terms of age, sex, education, social class or religious convictions. OBEs can happen to anyone. But OBE experients do tend to be more apt at absorption, to be more likely to have lucid dreams, to practice meditation and to score higher on tests of hypnotizability.

Brain waves of persons in an OBE suggested "the subjects were awake and paying attention to something." None of the theories put forward to explain OBEs in current terms of psychophysiological functioning has been satisfactorily proven.

Dr. George lists many other references within the text which provide additional information on the topic, plus he lists several articles for further reading.

This is a well-organized book. Each entry is richly cross-referenced. The book is rounded out with an Appendix (about correlations), a Bibliography and a thorough Index.