To the architect Mies van der Rohe, that chilliest of masters, I owe a moment of astonishment, now a memory in crystal.

I must have been 11 when, late one snowy evening, I first looked down at the city from one of his apartments high above the traffic of Chicago's Lake Shore Drive. I had never seen a room like that. The outside wall was missing. Where other rooms had windows, and wallpaper, and baseboards, this one had, instead, a sheet of floor-to-ceiling glass. The sky was gray, the lake was gray, snowflakes muffled sound. For many years thereafter, I thought I'd be an architect, an architect like Mies, an orderer of chaos, an opener of walls. I had never known a space so thrilling. It was like being in a heated cave on a high black steel cliff. There, beyond one's toes, the taillights on Lake Shore Drive were rubies on a string.

John Cage, the composer, comparably entranced, once watched a storm above the lake from one of those apartments. He said, "Wasn't it splendid of Mies to invent the lightning?"

The photographs and drawings, the models, chairs and tables in the "Mies van der Rohe Centennial Exhibition" at the Museum of Modern Art revive that sense of awe. He made extraordinary pictures. His buildings may suggest the most delicate refinements, but his freehand charcoal drawings have an unhesitant assurance, a muscular self-confidence that takes the breath away. His floor plans are impeccable. His furniture is timeless. Long before his death in 1969, he must have been aware that his designs had changed the look of the cities of the world. No architect of our age has had an influence so broad.

Once he was regarded as the most rigorous of rationalists. But that is true no longer. His vision still seems diamond-hard. But now we see its flaws.

The Modern's exhibition -- drawn from the 20,000 photographs and drawings, documents and models, in the archive Mies established there -- is dense and magisterial. It could not be much improved on. But something dark and troubling gnaws at its lucidities. Nobody who loved him once, who felt he honored truth, can see his retrospective without feeling to some small degree misled, abused, betrayed.

Glass-and-steel curtain walls no longer evoke wonder. There is no doubt that the Miesians, especially the lesser ones, have done their master damage. They promised they would build us cities bright as jewels. Instead they gave us Rosslyns, Sixth Avenues and K Streets. While pretending to the high road of clarity and logic, they instead took, in lock step, the shortest of the shortcuts toward low-cost-per-square-foot profits. "Less is more," they chorused, and for a while we believed them, until Robert Venturi, the first architect to see what that imperial guard was wearing, countered with what has become countervailing dogma:

"Less is a bore," he said.

Mies van der Rohe's apostles still defend him fiercely. The history of art, they note, is full of such dilutions. Think of all the losers who tried to imitate Picasso. Think of all the hapless followers of Pollock who chose to splatter paint. We do not charge Le Corbusier with all of the disasters of high-rise public housing. Nor is "Broad Acre City," Frank Lloyd Wright's utopia, universally indicted for all suburban sprawl.

It is equally unfair, they say, to blame the Miesians on Mies.

But the Modern's retrospective does not absolve him of his guilt.

His art, despite its pristine beauty, is in crucial ways dishonest. Perhaps it is no wonder that many of his earliest, most widely honored schemes were never carried to fruition. His tripartite glass-clad tower for Berlin's Friedrichstrasse (1921), his curvilinear skyscraper of 1922, his Concrete Country House of 1923 and his Brick Country House of 1924 exist as designs only. His most telling early building, the German Pavilion he constructed for Barcelona's International Exposition in 1929, was a showpiece too. Every architectural student is familiar with its doorless floor plan, its podium and pools, its columns clad in chrome and its sliding marble walls, but its influence is based on photographs and drawings. It was dismantled when the fair closed. It only stood for a few months.

Many of his masterworks are theoretical designs. His structures, built and unbuilt, even those admired for the thoughts that they make manifest, promise something more than they actually deliver.

Mies, the last director of the Bauhaus, long has been applauded for his use of new materials (reinforced concrete, steel I-beams, glass), and for his wholehearted allegiance to an industrial esthetic. True, his buildings feel like prototypes, appropriate for any site. And they look as if they might have been factory-produced. But none except the least of them, the structures of his final years, were helped in any real way by modern mass production. Most were built by hand.

Their superb details, in consequence, were fabulously expensive. The plain white wide-flanged steel columns that float his famous Farnsworth House of 1946-1951 are anything but plain. They were sandblasted until satin-smooth and then painted and repainted until their surfaces were flawless. The wood-walled bath-and-kitchen core in that pristine glass pavilion was built by a master cabinet maker. And it too cost a bundle.

"With how few means you can make architecture," Mies said in 1908. He often praised, as if he meant it, "economy" and "clarity" and "the materials of our time." "No noodles," he insisted in 1923, and "no armored towers . . . That is to say, skin and bones building." He is often thought a minimalist, a foe of inessentials. He was nothing of the sort.

Mies, throughout his life, insisted on his luxuries. He was no man of the people. His father, Michael Mies, was a stone mason in Aachen, Germany, but Ludwig Mies, his son, yearned for higher worlds. Disappointed with his name ("mies," after all, means "miserable"), he added on the "Rohe," his mother's maiden name, and then inserted an invented "van der," which gave him, he supposed, a nice touch of class. As a young man he affected a monocle and spats. His suits were made by hand. His cigars were from Havana. His apartment in Chicago was neither large nor grand, but he kept both cook and butler.

The interior materials he employed with cost-be-damned insistence made his frill-less structures gorgeous. The cafe' he designed in 1927 was hung with draperies of velvet and black and yellow silk. One free-standing curving wall in his famous Tugendhat House of 1928-30 was sheathed in striped macassar ebony; a second wall was clad in onyx dore', a rare and precious stone veined in white and gold. The draperies were beige raw silk, black silk and black velvet. The cushions of the metal chairs, all specially designed, were covered in white vellum or emerald-green leather. The Barcelona Pavilion was similarly appointed. The floors were clad in travertine, the smooth exterior walls in highly polished slabs of green, book-matched marble. The pool was lined with dark green glass. The famous Barcelona Chair, initially designed as a kind of throne for the ceremonial visit of the king of Spain, boasted cushions of white kid. So much for economy.

Mies understood full well that you cannot strip the stripped, that in minimalist building the role once played by ornament is instead fulfilled my rightness of proportion, perfection of the details and richness of materials. But his hostility to "noodles" only went so far. He frequently employed glued-on decorations. The black I-beams he attached to the facades of his Lake Shore Drive Apartments and his D.C. Public Library, like the more expensive bronze ones of New York's Seagram Building, serve no useful purpose. They are rhythmical devices, there to please the eye.

Almost all his rules are less rigid than they seem. Consider, for example, his ceaseless praise of "logic."

Logic might suggest that an architect so fond of glass would have thought about the shielding of south facades from sunlight. But Mies paid small attention to such functional demands. (On Lake Shore Drive he "solved" the problem of the sunshine by insisting that all occupants hang the same beige drapes.)

He cared nothing about neighborhoods. He responded to environments only when it suited him. By 1957, when he began designing the gracious, shade-providing overhanging roof of his Bacardi Office Building for Santiago, Cuba, he "was ready to admit," observes Arthur Drexler, director of MOMA's department of architecture and design, "that sunlight in Cuba was different from sunlight in Chicago."

But Cuba's light is different, too, from that of Mies' Germany, a nation whose "gray heavens" he often claimed to love. Yet in the early 1960s, when he conceived his scheme for the New National Gallery in Berlin, he employed an overhanging roof like the one designed for Cuba. Sunlight had nothing to do with that flat roof in Berlin. He just liked the way it looked.

It was the look of things above all else that governed his designs. Again, so much for "logic." His Farnsworth House in Plano, Ill., has a floor that seems to hover five feet above the ground, thus ackowledging, he claimed, that region's frequent floods. But that most elegant of buildings ignores Plano's steaming summers (it has no air conditioning) and ferocious mosquitoes (its doorways have no screens) and chilling winter wetness (the heating is so ill-designed that when it's cold the walls of glass stream with condensation).

When it came to building undifferentiated spaces, say convention halls or lobbies or open office floors, Mies was at his best. But he stubbornly refused to bend form to function. The little chapel he designed for the Illinois Institute of Technology might well be a boiler plant, a warehouse or a building housing classrooms. That his New National Gallery in Berlin uncannily resembled an office he'd designed for a manufacturer of rum did not bother him at all.

The museum in Berlin is an elegant, imposing tour de force of engineering, but a poor place for art. The sculptures and the pictures have been shoved into the podium on which its grand hall stands. That small part of the building that serves as a museum might as well be underground.

Mies in many ways was a Hellenist at heart. Like many other German artists of his day, he traced his love of clarity and order to the Glory that was Greece. His marching steel I-beams, brick piers and chromed columns evoke the arcades of classic Attic temples. So too do the podiums on which his shrine-like buildings sit.

His lifelong love of glass also ties him to his time. "In the years before and just after World War I," writes Robert Hughes, "German architects spun endless fantasies on the theme of glass . . . Like virtue itself, it was pure, unyielding, readier to break than bend. It was associated with the Holy Grail, with ice-caves, mountain peaks, glaciers -- the whole machinery of Romantic subliminity, as passed down from Casper David Friedrich Philipp Otto Runge, through Wagner and Nietzsche to the new century."

"Deutsch sein heisst klar sein," observed Hitler. ("To be German means to be clear.")

Glass admitted of no compromise. It was just the right material for an artist as austere, as inflexible as Mies.

He never paid much heed to his clients' complex programs. His Friedrichstrasse Office Building reaches to the curb so that, had it been built, passers-by would have had to step into the street. Nor was he much concerned with his clients' feelings. When Dr. Edith Farnsworth -- first his lover, then his client, and after that his enemy -- looked back at their relationship, she bitterly described him as "simply colder and more cruel than anybody I have ever known."

The master who emerges from Franz Schulze's new biography was selfish, stubborn, stolid and sometimes poisonously mean. He quarreled with Frank Lloyd Wright. He quarreled with Philip Johnson. He had numerous affairs, but was strangely cold to women. In 1938, when he fled Nazi Germany, he left his estranged wife, his three young daughters and his mistress, too, behind.

His politics were flexible. In 1926, Mies designed a stunning monument for the martyred Rosa Luxemburg, a communist shot down in 1919 (Mies' structure of used brick was torn down by the Nazis in 1933.) But he built for Hitler's Reich as well.

Steel rusts and marble cracks, but people are not perfect, and cities are not either. But Mies seemed to believe that theoretical perfection -- clarity of image, nicety of detail, and rightness of proportion -- would somehow conquer time. Until late in life -- when a kind of laziness, a willingness to grind it out, overtook his principles -- he was adamant as an artist.

The Modern with this show, which closes April 15, seems to be suggesting that Mies may yet retrieve his towering reputation. But I doubt it. Post-Modernism's silliness, its disposable materials and fanciful excesses, may soon fall out of fashion. The lucidity and rigor and unassailable precision to which he pledged his art (when it suited him to do so) may soon return to favor. But Mies' day is gone.