THE SLEEK Monorail train glides softly high above the swampy Florida flatlands, a realm of scrub pine and murky pools little changed by the onslaught of civilization. And then, in a moment's sweeping curve, the train descends into a gleaming stainless-steel-and-glass city, Future World at Epcot Center, Walt Disney's version of the 21st century.

The sudden juxtaposition of primal landscape and the towering Geosphere, the futuristic symbol of the new theme park that opened Oct. 1, is startling. But before the Monorail comes to a stop, it offers up yet another panorama to rattle the brain.

On the shores of a large lagoon, just beyond the world of tomorrow, clusters a pristine community of nations--World Showcase--where the Eiffel Tower shares the horizon with other wonders: an ancient Chinese temple, a Mexican pyramid, castle walls of medieval Germany, the enduring British pub.

If initially befuddling, this schizophrenic entrance to Disney's $1-billion attraction near Orlando is nevertheless a highly dramatic spectacle, which is what one expects from the creative entertainment minds that produced the successful Disneyland and Disney World make-believe parks.

Whether the latest addition, twice the size of Disney World four miles distant, captures the imagination of the American people as did Mickey Mouse's two magical kingdoms remains to be seen. Mickey appealed to our hearts, giving the child in us all the chance to live out our dreams. In an escape into fantasy, we can fly with Peter Pan over the rooftops of London Town.

Epcot, a decidedly unmagical acronym for Experimental Prototype Community of Tomorrow, is aimed at the intellect, where our curiosity can be stimulated by tentative answers to the age-old questions (raised this time by a soundtrack voice on Disney's journey through Spaceship Earth):

"Who are we?"

"Where have we come from?"

"Where are we going?"

When the Monorail doors pop open automatically, visitors emerge to find themselves near the foot of the 18-story Geosphere, amid a smiling Disney population garbed in trimly efficient "Star Wars" smocks. Seen from anywhere in the park, the silver sphere (from afar it looks like a dimpled golf ball) is a guide to keeping one's bearings. Inside is Spaceship Earth, where Disney's venture into the future begins.

Step aboard the endless chain of cars and disappear into the misty dark on a trip that traces the history of communication from caveman grunts to computer chatter. The cars climb steeply, like a roller-coaster just before the big plunge. Eerie music reverberates in the black, broken only by sudden flashes of simulated lightning.

Disney, passengers quickly realize, is going to entertain while serving up the educational stuff. Scare 'em a bit to keep their attention.

Up the cars go, passing minutely detailed tableaus: a lifelike Phoenician trader carries knowledge of the alphabet across the seas of the ancient world; a Roman ruler dispatches a messenger by horse along the roads of empire; a supine Michelangelo, resting on a creaky platform, adds finishing touches to the Sistine Chapel.

Here and there, a bit of fun keeps the lesson light. While a stern-faced monk laboriously hand-copies a Bible, his roly-poly companion snoozes away the afternoon.

Into the 20th century, and the pace escalates: movies, radio, television, computers. What next? Suddenly the car plunges back into blackness, spinning 180 degrees before giving passengers a glimpse of distant Earth high overhead in a sea of stars. For a second, the car seems poised in infinite space. And then it begins its slow, steep, backward descent. The passengers have become space travelers departing our planet.

From Spaceship Earth (the ride lasts about 10 minutes), Epcot visitors scatter to Future World's other pavilions, where similar shows incorporate Disney's famous animated figures--called "audio-animatronics"--and deft use of multidimensional movie photography and stereophonic sound to bombard the senses.

The Universe of Energy, with a rooftop solar system that can generate 70,000 watts of electricity, explores the forces that power our society, from the surging seas to nuclear fission.

The World of Motion (a 14-minute ride) traces modes of transportation, again from the age of the cave dweller (Mr. and Mrs. Dweller put down their hunting clubs to rub weary feet) through America's love affair with the auto (double-dating teen-agers head for a '50 s drive-in movie) to outer space filled with space vehicles darting across the universe. Don't take it all too seriously, particularly the flying carpet sailing above.

In The Land, the pavilion that provides the most tangible examples of how advancing technology is meeting the challenges of the future, passengers board small barges to float through an intriguing greenhouse. Here fruit, vegetables and grain are being grown in novel ways--in sand or without any soil at all. This could be a way, Disney suggests, to feed the world's growing population as arable land disappears.

As the barge drifts by a wood-framed farmhouse, a scruffy dog barks, chickens cackle and a pair of porkers look up with a grin. What's that smell? Another Disney innovation: authentic barnyard, wooshed past your nose by the Smelitzer machine.

Beyond Future World, Epcot changes character completely in World Showcase, reached by a mile-long walk around the 40-acre lagoon, a cruise on the lagoon ferry or a ride on a double-decker bus off London's streets. It is hard to understand what the Disney people had in mind by combining such diverse attractions as World Showcase and Future World in the same park, unless it is to answer the question: "Who are we, the peoples of the world?"

After watching the mechanical creatures of Future World, however, it's a relief to meet the real-life folks from China, Japan, Mexico, France, Germany, Canada, Italy and the United Kingdom, who serve up ample quantities of their native food and arts. A lively mariachi band on the steps of an Indian pyramid signals that school is out, and it is time for fun.

Stroll into St. Mark's Square, and you're likely to be caught up by Il Teatro di Bologna, three street comics who pull the audience into their hilarious performance of "Romeo and Juliet."

"This story happened a long, long, long, long time ago," begins the narrator, dressed in Renaissance garb. "Lady," she says, pointing to the gray-haired woman sitting beside the plaza fountain, "you'd remember it." And the insults and the jokes flow.

Down the walkway, in front of the miniature garden that adjoins the Mitsukoshi department store of Japan (since 1673), a street artist molds small balls of wax into graceful dragons. These he hands to spectators.

Duck behind the elegant Les Chefs de France Restaurant, supervised by three of France's most famous chefs, to find the pastry shop. If you are lucky, Roger Verge, one of the trio, may be brushing the glaze on an apricot tart just out of the oven. With a cup of tea at your table, you can watch the crowds stroll by in the shadow of the Eiffel Tower.

Epcot Center has the potential to keep the ticket-buyers returning, if the generally favorable comments heard during opening week are any indication. Eight million visitors are estimated for the first year, an average of 22,000 a day.

The garden setting around the World Showcase Lagoon is stunning: fountains and flowers, park benches under shady trees, balloons and colorful banners, the eye-dazzling blue and green temple of 15th-century China, the waterfall spilling over a Canadian mountain. These are the ports of call of our dreams, romantic, friendly--and Disney clean, kept so by an army-sized crew dressed up to look like foreign legionnaires.

Indoors, the elaborate woodwork, iron work and stained glass in the chic specialty shops, selling fairly costly perfumes, jewelry, porcelain and other luxury items, is evidence the Disney people spent their $1 billion for quality.

And there are things not found elsewhere: A delicate dragon kite appears to hover within arm's reach in "Magic Journeys," a 3-D movie in the Journey Into Imagination pavilion of amazing technical quality. It is a sure-fire audience pleaser.

In the China pavilion, a 360-degree movie screen surrounds the viewer with seldom-seen views of that country's ethereal mountain and desert beauty.

Still, there are disappointments. Mechanical breakdowns plagued Epcot's opening, although those are expected to be resolved soon. Large crowds resulted in long lines, which has been an annoyance at Disneyland and Disney World for years. More restaurants (with an improved reservations system) and additional pavilions to be opened in the next two years may ease the crush.

Commercialism is overly evident in the pavilions sponsored by corporate America. One leaves the General Motors-sponsored World of Motion, for example, with the impression that to GM transportation of the future is a sleek new Chevy or Pontiac. There's even a new-car showroom at the exit. What about mass transit for our auto-clogged cities? No answer is readily found here.

World Showcase, with its limited goal of offering a taste of each nation to the multitudes who may never travel abroad, appears to have achieved its mission, though additional touches are needed--such as vendors selling authentic Italian ice cream instead of blandly familiar ice cream sandwiches.

Future World, however, falls short of what it might do to give us insights to life in the next century. The focus on the past in the tableaus leaves a visitor still asking: How will we live? What advances in health care can we expect? Perhaps more answers will come in the three major pavilions to open between now and 1984.

At opening-day ceremonies, Card Walker, Disney's chairman of the board, said the dream behind Epcot was "to entertain," "to inform" and "to inspire." Entertained, we are, and that's no little accomplishment, even for 15 bucks a head. The Disney people still know how to put on a show. We will have to wait and see if they can realize the rest of the dream.