We are not alone - but we are very funny

LITTLE GREEN MEN By Christopher Buckley Random House 288pp. $23.95

The key to an April Fools' Day prank is plausibility. Tricksters crave that perfect blending of the ordinary and the ludicrous that can spin victims into a moment of comic panic.

Years ago, a friend of mine and I taught at a conservative private college in the Midwest. One semester, he hung a series of his quiet, muted paintings of the Maine coast in the school lobby. My stage was set. Using office stationary, I wrote him a letter - from the chairman of the college - complaining about the shockingly pornographic nature of his paintings. I concluded gravely, "The trustees will be meeting soon to discuss your employment status."

Kids: Don't try this at home. My friend swallowed it hook, line, and sinker - and then swam off in a rage toward the chairman's office. Fortunately, someone caught him, or the trustees would have soon met to discuss my employment status.

April 1 is obviously Christopher Buckley's favorite holiday, too. Today the comic author releases a hysterical novel called "Little Green Men." It's a prankster's greatest fantasy.

The story opens on Washington's most pompous and feared political commentator. Every Sunday morning, John Banion runs the capital's most powerful elected officials through a brutalizing interrogation on his top-rated TV show, sponsored by a leading maker of electrocution chairs.

Senators and presidents sweat under Banion's owlish gaze, but "in a medium glutted with sound bites, people were happy to come on and have 20 minutes of national TV exposure all to themselves, even if Banion sometimes extracted an admission price of flaying them alive, on air."

Far from Banion's rarefied world, Nathan Scrubbs is "waiting for his computer to advise him that somewhere in Indiana another housewife had been abducted and sexually probed by aliens in a flying saucer."

Poor Scrubbs works for a supersecret government organization called MJ-12. His job is to keep "the taxpaying U.S. citizenry alarmed about the possibility of invasion from outer space, and therefore happy to fund expansion of the military-aerospace complex."

The project had started modestly by towing pie-shaped reflective disks around the desert sky, but "when the thrill of disabled vehicles and freaked-out pets wore off," MJ-12 had to start staging alien abductions. "This was trickier," Buckley notes. "For one thing, it meant finding dwarfs with security clearance. For this reason, aliens have gotten considerably bigger over the years."

In a moment of recklessness, Scrubbs decides to defend the nation's new space station by converting its most vociferous critic: John Banion.

Before high-ranking officials can call off their faux invaders, Banion is abducted - twice! - by aliens and becomes the world's most famous UFO proponent, the "Paul Revere of the Milky Way."

Washington has endured all kinds of shocking conversions, surprises, and transformations, but for this there is no precedent. His wife pleads, his friends intervene, the press attacks, and his sponsor cancels, but no one can derail Banion's efforts to awaken the American people to the alien threat.

He quickly repackages himself on a new TV show that looks "like the bar scene from 'Star Wars.' " More powerful than ever, though with a decidedly different group of fans, he calls for a Millennial Man March on Washington to demand congressional hearings on alien abduction.

"My name is John O. Banion," he tells the adoring millions on the Capitol steps, "and I am an abductee."

"Ich bin ein kook," reads the next day's headlines.

Buckley's collection of alien fanatics is worth more than a ton of antimatter. (The Tall Nordic Singers perform "We Are the World" during the Millennial Man March.) It's a decidedly bawdy book, with that classic Monty Python mixture of highbrow satire and lowbrow ribaldry. His flights of comedy zigzag through the story like UFOs over Area 51, and his ear for the ridiculous is out of this world. Tuck "Little Green Men" away for a quiet night in the crop circles.

* Ron Charles is the Monitor's book editor. Send e-mail to charlesr@csps.com