James Randi obviously relishes the career he has made for himself as a skeptic, puncturer of myths, and archenemy of pseudoscience. "Flim-Flam" is a compendium of his favorite shams, some of which he claims to have exposed himself. In other cases, such as the photograph of "fairies at the foot of the garden" taken by two English girls and made famous by Arthur Conan Doyle in 1920, Randi recounts the work of earlier investigators. However, he does take a look at the photos for himself, and seems to find new evidence for disbelief.

The method is peripatetic: Randi moves about the terrain with no clear design, dismantling myths and mystical claims as he stumbles on them. The style is pugnacious but amusing in its eccentricity. For example, the chapter attacking the Bermuda Triangle mystery begins: "It is careless of a man to fail to sufficiently research a subject . . . irresponsible for him to resist telling the facts . . . irresponsible and callous for him to continue to misrepresent matters about which he has been informed to of these failings." One has to acquire a taste for this.

Converts are the most ardent missionaries. The same may apply in inverse fashion to disbelievers. Perhaps one must have lost faith in flying saucers to be interested in the kind of detailed refutation that Randi delivers. But Randi himself gives no hint that he was ever enchanted by pixies or men from Mars. He offers a sober reason for doing what he does.

Before this, Randi made himself into a very successful magician. He has performed at the White House. His idol is Houdini, who also liked to expose frauds. By Randi's account, his own achievements in magic led directly to his present avocation, for he says he cannot abide the techniques of people like the psychic spoon-bender, Uri Geller, of the transcendental levitators who follow in the holy footsteps of the Maharishi Mahesh Yogi.

More than that, Randi says, these peoples' pretensions are outrageous. He considers it a matter of professional ethics. Those who make a living by deceiving the public must have standards, and they must police their ranks. Unlike doctors, magicians have no professional review boards. But they have Randi. In his view, the worst offenders are those who claim supernatural powers or fail to see that the whole point of the business is to entertain, not to gain power.

Jim Jones, the mad preacher who led his gullible flock to suicide in Guyana, is the chief example of a magician gone wrong. Stopping such people before they get launched is important work, Randi says. He chastizes an editorial writer at The Washington Star for missing this point and belittling the 1977 annual meeting of the Committee for the Scientific Investigation of Claims of the Paranormal, a debunking society of which Randi is a member. The editorialist saw it as "overkill . . . gnat-killing by sledgehammer . . . machine-gunning of butterflies."

Randi responds with bluster. The editorial writer "never saw the distraught faces of parents whose children were caught up in some stupid cult that promises miracles. . . Mister, go dig up one of the 950 corpses of those who died in Guyana and shout in its face that Reverend Jim Jones was not dangerous." This is Randi at his bullying worst. Usually the demolition proceeds with more grace.

Because it is difficult to take apart a psychic event after it has happened, Randi occasionally tries to be in on the action, playing the role of a double agent. Astrology is a phony science, and an easy one to practice, the author claims. To demonstrate this, Randi set himself up on a radio talk show as an "astro-graphologist" who could read the future in handwriting samples. Listeners dutifully mailed in samples, but Randi never examined them. Instead, he repeated bits of readings given by a professional astrologer months earlier to people in a television studio. Randi's show was very popular while it lasted, and the clients apparently found him tremendously perceptive. The trick, of course, is that astrological forecasts are written so that everyone can find some truth in them.

In another case, Randi ran a test of water dowsing. He has offered to give $10,000 to anyone who can demonstrate psychic powers under controlled conditions, and a group of experts in locating underwater streams rose to the challenge. Randi constructed a test field with a pattern of water pipes and switching valves that allowed him to change the course of the water's flow underground. Then he invited the dowsers, using y-shaped twigs or metal rods, to trace the flow of water. Of course, they wandered all over the lot, traced water when none was flowing, and generally made themselves look silly. As is typical of true believers, Randi notes, they were not at all embarrassed. It was he who felt awkward.

Similarly, but not so thoroughly, Randi flays a variety of other occultists: psychic space travelers, table-tipping mediums who speak with the dead, believers in Von Daniken's theory of ancient astronauts, mind readers, and psychic surgeons. Needless to say, the believers will not be swayed by his arguments. They claim, for example, that Randi has never truly disproved the paranormal powers of Uri Geller. But Randi has put together a short, entertaining guide for skeptics, an encyclopedia of current witchcraft.