Cats" is sensational -- a purrfectly original, pawsitively spectacular musical.

Call it a fantastic Beaux Arts ball or a Close Encounters of the Feline Kind; there is nothing like it on Broadway, nor is there likely to be for the next five years, which is a modest estimate of the run it is sure to enjoy.

Populated by 26 lithe actors masquerading as cats (unless it is 26 cats masquerading as actors), it creates a whole world -- mystical, magical and capricious -- in the Winter Garden Theatre, where it opened last night.

The Winter Garden itself has been turned into a cosmic garbage dump. Junk has been strewn over the stage, across the balconies and up to the very rafters. Like hot coals in the debris, dozens of eyes glow in the dark, while strings of crisscrossing lights form a starry canopy overhead. The setting alone could launch a radical new trend in discotheques.

Then, casting caution to the wings, they materialize -- Rum Tum Tugger, the cussedly independent cat; Old Deuteronomy, the wise patriarch with a biblical coat; dapper Bustopher Jones, the Cat About Town; Grizabella, the glamorpuss who's fallen on hard times; cozy Jennyanydots, the Old Gumbie Cat, who feels obliged to put cockroaches and beetles to productive pursuits; criminally quicksilver Macavity, otherwise known as the Hidden Paw; and Gus, the gummy theater cat, still dreaming of his days of glory on the stage. All told, there are dozens of them, swishing their tails, baring their claws, preening their manes and generally grooming their personalities, which are not unlike yours or mine.

On the surface, "Cats" would seem an utterly questionable affair. Its genesis is a handful of lighthearted poems that T.S. Eliot, not normally a playful poet, wrote for his godchildren under the title of "Old Possum's Book of Practical Cats." The music is by Andrew Lloyd Webber, a composer whose imagination seems to soar in direct proportion to the unlikeliness of his subject. The score -- as dramatic as "Evita," but warmer; as spunky as "Joseph and the Amazing Technicolor Dreamcoat," but more inventive -- represents his fullest, most appealing work to date.

But what makes "Cats" more than just a parade of the animals is the collective effort of a remarkable creative triumvirate composed of director Trevor Nunn, choreographer Gillian Lynne and designer John Napier. They have given "Cats" a look and a feel all its own. The show may take place in the refuse of civilization, but it converts a scruffy, scrabbling arena into something quite sublime. In costume and choreography, it is a perfectly observed anthology of the sinuous manners and comical mannerisms of our four-footed friends. Yet it respects the enigma that lurks in every cat's gaze. Without being pretentious, Nunn and his collaborators ultimately suggest that as a species, cats are onto something we humans have yet to figure out: the mystery of creation.

Many members of the vast paying public may be lining up for something else, something, I suspect, akin to the collected antics of Garfield and Krazy Kat. They will be getting a different show entirely. A far better one. What could have been merely a cute conceit -- or worse, a precious one -- has acquired the dimensions of a rare theatrical vision.

"Cats" takes most of the first act to establish its curious credentials and dispose of what are frankly its two weakest numbers. The Gumbie Cat (Anne McNeeley, looking like Angela Lansbury in a raccoon coat) presides over a somewhat pedestrian production number, leading a band of beetles through a tap-dance routine that, for all the inventive costuming, is still just a tap-dance routine. And there's a confusing and pointless battle between "the Pekes and the Pollicles" (Pekinese and Yorkshire terriers, apparently) that is largely tangential to the matters under consideration, even though the dogs are played by cats.

But the second act is a succession of dazzling numbers, each one surpassing the previous, until "Cats" goes through the roof. Literally. As they do every year, cats of all stripes and spots have gathered for The Jellicle Ball under the sponsorship of Old Deuteronomy (Ken Page, who once played the Lion in "The Wiz," so he's drawing on experience). Before the dawn's early rays, Old Deuteronomy will choose the cat who will be permitted to ascend to heaven, the first stop on the road to reincarnation.

Meanwhile, the various cats tell their stories and indulge in their fantasies (not unlike "A Chorus Line," if you stop to think about it). Rum Tum Tugger (cocky Terrence V. Mann) prides himself on his contrary disposition and a sleek black-leather appearance the Fonz might envy. Gus, the palsied theater cat (Steven Hanan), muses about days of bygone glory, when he once received "seven catcalls," then in his imagination reenacts his celebrated role in "Growltiger's Last Stand," as a swashbuckling pirate taking on a battallion of Siamese warmongers.

Skimbleshanks (Reed Jones), the railway cat, shows how he keeps order on the Sleeping Car Express, and the other cats oblige him by assembling a steam-puffing locomotive out of the trash at hand. Spinning on like a top, Mr. Mistoffolees (Timothy Scott) proves he's the master of magic and conjuration, not to mention wildly nimble feet.

Then, there's Grizabella (Betty Buckley). Once a beauty, now a sad, half-mad derelict, tottering on high heels, she's been hanging about the fringes to the general disdain of her peers. Toward the end of Act II, however, she gets to vent her heartache in the plaintive "Memory." The ballad is one of Webber's best and Buckley, in a performance that seems to preempt this year's Tony competition, sings it with stunning anger and pathos.

Just when you think the show has hit its peak, though, Old Deuteronomy taps the wasted Grizabella for resurrection. A mammoth truck tire, buried in a mound of refuse, rises slowly in a whoosh of smoke and a blaze of lights. Out Spielberging Steven Spielberg, the unlikely spaceship lifts her up through the twinkling lights, up through the parting clouds, up and out of the very theater itself. This sort of mind-boggling climax is going to make life very difficult for future Broadway musicals.

Nunn and Napier both pooled their skills for last year's "Nicholas Nickleby," and "Cats" bears witness to their extraordinary concern for details. The crook of a passing paw is staged with as much care as the crackle of electricity that precedes Macavity's baffling vanishing act. Without ever jeopardizing the overall sense of ensemble, the cats of the chorus are as individualized, and quite as wonderful, as those who get to step out of the litter. The cost for such extravagant punctiliousness is said to be in excess of $4 million. You can see every cent.

Advance word from London, where "Cats" continues to triumph, has long indicated that something special was up. That sort of talk invariably produces a "show me" backlash. "Cats" can settle back on its haunches, confident it can meet the expectations of the throngs at the door. It has the life of nine Broadway shows.

CATS. Music by Andrew Lloyd Webber. Based on T.S. Eliot's "Old Possum's Book of Practical Cats"; director, Trevor Nunn; designer, John Napier; lighting, David Hersey; choreography, Gillian Lynne; sound, Martin Levan. With Steven Hanan, Betty Buckley, Bonnie Simmons, Anna McNeeley, Timothy Scott, Ken Page, Harry Groener, Reed Jones, Terrence V. Mann, Kenneth Ard. At the Winter Garden for a long time.