Hollywood came to Main Street with full bravado. ''Buy our dreams,'' said its most visible manifesto, the picture palace. ''Make them your own,'' whispered the architecture.
''Follow us with mellow incandescent lights, beneath glittering glass chandeliers, by chairs fit for Cleopatra and rugs, all starred and moon-filled, leading to romance on the silver screen.''
''We sell tickets to theaters, not movies,'' said impresario Marcus Loew. Pay your money, get the pyramids, Mayan tombs, hanging gardens, Fu dogs, columns topped off with enough ornament to make a Roman weep. Ohhh, to have lived in the days of the twinkling stars of stage, screen and radio.
Is there anything more American than this mix of the box office and the beautiful? Anything more revealing of the soul of the nation than the ''American Picture Palaces'' which rose across the country, and appear again in an exhibition at the Cooper-Hewitt Museum through Feb. 27?
Bearing the dates of the 1920s when they rose (as their hero might have said) faster than a speeding bullet, the Golden Age of movie theaters is set before museum-goers in objects, drawings, photographs that fill out most of the second floor of the Smithsonian Institution's National Museum of Design here.
Gaudy, exotic, and flashy, their baroque designs and bombastic marquees disguised the remarkable technological invention and irregular rooms adroitly laid out within.
''Of all buildings, none are more fascinating to design, nor more difficult to construct,'' the show's organizer, David Naylor, quotes a British architect in 1931.
''Aside from the skyscraper, no building type is more clearly representative of twentieth-century American architecture than the movie palace,'' Naylor writes in ''American Picture Palaces: The Architecture of Fantasy'' (Van Nostrand Reinhold; $29.95), the fascinating book from which the exhibition is drawn.
The show begins as the interior of the picture palace began: with seats gilded to match their shape's princely command and a model usher poised before a brass ticket chopper. It notes at the outset, the 50th anniversary of Radio City Music Hall, built in 1932 and celebrating its birthday with the good fortune of survival.
The show as a whole makes a positive statement on the fate of these Main Street survivors. It is a national look, displaying the Midwest main street, theaters in Kansas City or St. Louis as well as Hollywood Grauman Chinese ones that have endured or enjoyed adaptations. Happily, most of the labels describing these showplaces do not bear the tragic suffix ''demolished.''
The section on ''Conversions'' does show some sad mementoes - a theater in Detroit gutted out, symbolically enough, as a parking garage in Motown. But, by and large, the adaptations offer more appropriate uses for the enormous shells of an industry that survives nowadays with small multi-cinemas more than mega-spectacle ones. There is a Symphony Hall, a retail store, a gym, a church . . . and the number of uses could have been multiplied if photos of the smaller cinemas had supplemented these stars.
Still, superlatives, the starriest of the star-studded structures, is what the picture palace and the ''American Picture Palaces'' are about. The show provides an engaging tour through the luminous crowd-culling designs, and a corollary inquiry into the people who flocked to them.
What manner of practical folk need spend their days and take their entertainment in the Forbidden City of Peking? Have rams' heads embroidering their money-machines? And mosaics reminiscent of the Alhambra embroidering their ordinary fire escapes?
What kind of a trip did moviegoers take as they walked through, say, the Loew's State lobby in Syracuse with its inferno-red ambience and temple-like atmosphere? What did they see of the half-million plus spent for Italian marble columns in Rapp and Rapp's Paramount Theater in Times Square?
Clearly a good deal. If the New Yorkers passing by the Cooper-Hewitt photos even now are any indication, the loss of the Morosco and Helen Hayes legitimate theaters causes clucking and sad comments from the visitors here. A look at the bygone Roxy produces sighs from those who remember it. The song ''What's Playing at the Roxy'' seems etched as deeply in their memories as architect W. W. Ahlschlager's abundant ornament, carved to a fare-thee-well on its walls.
Opulence in art, the they-don't-make-'em-anymore approach to architecture, has validity in a period that has disowned the fantasy of peacock lights (Radio City Music Hall) inside or the delineating of architecture with a delightful punctuation of light bulbs on the outside (Pantages Theater). The trim transforming countless facades with an icing of wedding cake elegance has no sequel. There is no ''Son of Loew,'' no ''RKO Keith II.''
Lounges and coatrooms, even billiard parlors, powder rooms, and chambers for cigar smokers, all fitted out with appropriate aplomb, don't secure the attention of the exteriors and screen rooms in the show. But they too are a loss.
Spaces like the Africa room at Loew's Ohio in Columbus, ''a cultural safari, '' by Anne Dornan, chief designer, provided enough wild animals to make Tarzan forget companion Jane; while the Vanderbilt's New York townhouse, transported to a women's lounge in Loew's Midland, Kansas City, would have comforted the cast of the ''Mikado'' with its oriental splendor.
In short, no secular architecture has ever transformed both the inner and outer world of Americans as that on view here. Our cities and towns glistened with the design mementoes of ''magicland,'' and the fantasy to visit worlds beyond the routine was carried to the ''nth'' realm of the imagination by these interiors.
If the entertainment industry's design symbols revealed an architecture of folly and excess at times, their heirs - the small TV set and Main Street drive-in box - boast no life-saving illusions at all, provide no parallel delights and hence no spiritual sustenance, much less two-hour trips to Shangri-La these days.