The U.S. government confiscated secret Nazi anti-gravity technology at the end of World War II, and later may have tested it in aircraft that account for the rash of post-War UFO sightings. Some of that technology has probably made its way into the B2 stealth bomber. Some of it is probably so dangerous that it's buried away in secret government vaults.

In the post-X-Files age, this sort of conspiracy theory won't raise any eyebrows. What makes the allegations interesting is that they appear in "The Hunt for Zero Point," which is written by Nick Cook, for 10 years the aviation editor at Jane's Defense Weekly. Jane's is the bible of the defense establishment, known for its no-nonsense, nuts-and-bolts reporting. A former Jane's editor tackling this topic is enough to make you take a second look.

Although anti-gravity research ranks right up there with perpetual motion on the crank-o-meter, the idea of anti-gravity can't be completely dismissed. As recently as 1996 a Finnish scientist announced he could partially "shield" objects from gravity using spinning superconductors. Although most scientists are skeptical, NASA is interested enough that it's trying to replicate the results.

And certainly Nazi Germany was working on a lot of advanced technology by the end of the war, including rockets, jet fighters and nuclear power. The U.S. recruited some German scientists to continue their work in the U.S., most notably Wernher von Braun, the V-2 rocket scientist who later helped make the moon landings possible.

It's also clear that the U.S. military works on secret technology all the time -- about $11 billion worth every year in "deep black" programs that aren't even acknowledged to exist. The stealth fighter and B2 bomber were black programs for years.

So even if Nazi flying saucers sound nutty on the face of it, there's nothing crazy about Cook asking the questions he does. You might even call it courageous. It's the conclusions he reaches that are the problem.

Cook's search begins one day when a photocopy of a 1956 magazine article mysteriously lands on his desk. It's called "The G-Engines Are Coming!" and is illustrated with a drawing of a U.S. airman descending the steps of a floating, wingless aircraft. Cook thinks it's a joke, but gets interested when he sees aerospace industry leaders of the day quoted as saying anti-gravity could be the next big breakthrough.

He decides to call one of them, a now-retired engineer named George S. Trimble. A Lockheed Martin P.R. person, "Daniella Abelman," sets up an interview, then calls back and says Trimble has cancelled.

"I don't mind telling you that he sounded scared and I don't like to hear old men scared. It makes me scared," she tells Cook. "Let me give you some advice. Stick to what you know about; stick to the damned present. It's better that way for all of us.'" (Cook has changed "Abelman's" name, so there's no way to call her and see if she really talks like a character in a Tom Clancy novel.)

Of course Cook's curiosity is inflamed, and he tracks down Trimble in a retirement community in Arizona and -- oh, wait a minute. That's what you expect him to do. But here's what he says. "My great regret was that I couldn't contact George S. Trimble directly. Had I done so, I knew that Abelman would have gone ballistic. She'd told me to stay away from him and she had the power to ensure that I became an outcast if I didn't."

Unwilling to face the wrath of the flack, he retreats to the Internet where "in the silence of the night, I could roam ... and remain anonymous." He finds the story of Thomas Townsend Brown, a former Navy engineer who believed he could negate gravity using electricity and who by 1956 was demonstrating small, electrically charged flying disks. The military was briefly interested, but in the end issued a report that said there was no usable technology there.

But Cook notices something in a 1947 Army Air Force memo (famous among UFO buffs), in which Lt. Gen. Nathan Twining concludes that UFOs are real. Twining adds that it is "within the present U.S. knowledge" to construct similar aircraft, given enough money.

Cook concludes that by 1947 the U.S. must already have had a key component of UFO technology -- anti-gravity. That's why they weren't interested in Brown's technology years later. He suspects the technology came from Nazi Germany, and recounts allegations of German flying saucer programs from a few dubious books, as well as information he admits seems to have "magically appeared out of thin air ... passed down from one researcher to the next, without attribution."

He gets off of the Internet and starts searching through military archives for clues. He finds a few hints in old Army Air Force records on Luftwaffe technology, but nothing substantial. Then he reads that the SS was in charge of the most secret German technology. "I felt a constriction in my throat. I was so keyed, my breath was coming in short, sharp gasps." Don't worry, he's not having a heart attack. He just realizes he's been looking in the wrong place. He starts reading about the SS.

Soon we're off to Poland. A "researcher" named Igor Witkowski shows Cook an old mine, where he claims SS scientists worked on a machine called the Bell, a glowing, rotating contraption that used up a lot of electricity. "Word had it that the tests sought to investigate some kind of antigravitational effect, Witkowski said." Somebody else thinks it might have been a time machine. Then Cook finds yet another SS anti-gravity program, a flying saucer called the "Repulsine."

Cook concludes that an SS official named Hans Kammler had all of this technology boxed up and flown to a safe place, later trading it to the U.S. military for his freedom.

The U.S. government kept it all under wraps for years, but probably implemented some of it in the B2 bomber. Why didn't the U.S. make more widespread use of this technology? Partly because it would have disrupted the existing aerospace industry, with its expertise in winged aircraft. Partly because anti-gravity might tap into energies just too destructive to tamper with. And "... in the 1940s and 1950s, it wasn't as if the world really needed it."

It's a story that strains credulity. But unless we're after cheap laughs, our hope when we pick up a book like this is that the author will, against the odds, build a careful, reasonable and convincing case. Cook isn't that author.

The first problem is that Cook is no help sorting out the physics he's writing about. His explanation of "zero point energy" (a quantum effect caused by virtual particles winking in and out of existence) is acceptable. But he's also capable of explaining that the Repulsine made air molecules "pack so tightly together that their molecular and nuclear binding energies were affected in a way that triggered the anti-gravity effect." Both explanations sound equally weird to the layman. But the first is recognized science, the second pseudo-science.

OK, so physics is hard, and Cook is a journalist. But we should at least expect him to bring a journalist's care to the sources he uses and the conclusions he draws. Instead, we're bombarded with a hodgepodge of information trawled up from the Internet, other books and UFO and anti-gravity enthusiasts, along with some firsthand reporting. Although he makes a show of weighing this information with the critical eye of a trained aerospace expert, he doesn't prove worthy of much confidence.

A perfect example is his reliance on Witkowski, the Polish researcher, whose information is key to Cook's conclusions. Where did the information come from? Witkowski says a Polish government official (whom he refuses to name) allowed him to see some documents, but not make copies of them. Why does Cook believe Witkowski?

"Witkowski had been recommended to me by Polish sources through my work at Jane's as someone who was both highly knowledgeable and reliable ... Had Witkowski been in any way a lightweight, I would have turned around and got on the first plane home. But when I saw him, I knew he was OK."

Just as shaky are most of Cook's conclusions. For instance, the old Army Air Force memo in which Twining says UFO-type aircraft are "within the present U.S. knowledge" runs like a mantra through the book. Cook thinks it means that even in 1947 the U.S. could have built an aircraft capable of tremendous acceleration and instantaneous changes of direction, a craft that would require anti-gravity to work.

Twining actually says, "It is possible within the present U.S. knowledge ... to construct a piloted aircraft which has the general description of the object in subparagraph (e) above." What's that description? Metallic, saucer-shaped, quiet, no trail, capable of flying in formation, with a cruising speed of 300 knots. Right or wrong, Twining's not talking about the same astonishing capabilities as Cook is.

Or look at his conclusions about Kammler, the SS official Cook thinks traded the anti-gravity technology to the U.S. By the end of the war Kammler was the administrator in charge of most advanced research programs, including the V-2 rocket factories. But where's the evidence he traded any technology -- much less anti-gravity technology -- to the U.S.? Well, a lot of Germans with technological knowledge tried to cut deals with the U.S. Kammler's movements at the end of the war are mysterious, and there are contradictory reports about his death. Besides, Cook thinks it's the kind of thing Kammler would do.

"My feeling was Kammler would offer them something so spectacular they'd have no choice but to enter into negotiations with him."

In fact, a lot of the evidence here is based on Cook's feelings. A minor but typical example is a feeling he gets while reading a "recovered transcript," supposedly of a phone call between two Air Force officers discussing Brown's work. Gen. Victor E. Bertrandias is the chatty one; a general named Craig doesn't say much -- only "No" and later "I see." It's Craig who catches Cook's interest.

"The man's urbane delivery earmarked him, to me at least, as someone big in Air Force intelligence." All that from, "I see."

What is instructive about the book is the insight we get into how conspiracy theories seduce otherwise reasonable people. Like all of us, Cook knows that real conspiracies exist. No one questions, for instance, that military technologies are being developed in secret, and that the government "conspires" to keep details from the public.

But what do you look for when you think direct evidence has been withheld or suppressed? Before searching some old records, Cook realizes "it was inconceivable that the ... intelligence teams would have documented the discovery [of German flying saucers] for the world to read about ... I wasn't searching for the obvious, because the obvious would have been picked up by the censors." So Cook is reduced to ferreting out minor inconsistencies and odd, ambiguous details which he tries to puff up into proof.

Likewise, information that is available has to be suspected as possible government disinformation. Perhaps the military has encouraged UFO reports to disguise its own flying saucer tests. Maybe the mythical Philadelphia Experiment (in which a Navy ship was supposedly sent into another dimension) was really just a story designed to discredit Brown. But, since the best disinformation always contains a grain of truth, maybe there really is a connection between anti-gravity and other dimensions.

Using this reasoning, all bets are soon off, and almost anything you turn up -- lack of evidence, official denials, unsubstantiated rumors, wild conjecture -- becomes evidence for what you're trying to prove.

In the end, Cook's argument boils down to the old proverb he invokes several times -- Where there's smoke there must be fire. But sometimes, someone's just blowing smoke.