Architect Robert Venturi, whose words and (in lesser measure) works have had more influence on the theory and practice of contemporary architecture than those of any other individual, seems happily distracted as he regards a room full of his firm's drawings at the Octagon Museum.

The reason, he explains with a sudden cat-caught-the-canary smile beneath the rims of his bifocal glasses, is, "We're very busy."

Venturi has taken a late afternoon flight from his Philadelphia office to be present at a reception marking the Washington appearance of the traveling show "Venturi, Rauch and Scott Brown: A Generation of Architecture," which continues through June 9. He scurries from drawing to drawing with obvious pleasure -- "I haven't seen these for more than a year . . . I like the way they look in these small rooms" -- and yet his eyes are directed inward, as if his mind were still churning over a problem left on the drawing board back home.

"We're doing a couple of art museums," he says, "and a few office buildings, and then there's the urban planning work, and the Princeton buildings -- they've been very good to us at Princeton -- and the projects for the Philadelphia zoo."

Referring to himself and Denise Scott Brown, his wife and professional partner, he has said, "We have this theory that to be 10 percent better you have to work 100 percent harder."

No longer the theoretical enfant terrible of the architecture world, Venturi at 59 clearly is enjoying the work that new-found respectability has directed his way. In the past decade, and even more so in the last five years, he and his colleagues have at last been given the chance to put their provocative, productive theories into practice on a scale larger than that of the single-family house. "We are grateful to our swinging, Jewish, Pop Art clients whose little houses, alterations, sympathy and promotion have helped us weather nine years of almost-unsuccessful practice," Venturi and Scott Brown wrote in 1970 in one of the contentious essays they were writing frequently back then.

"These essays . . . [were] written in times of search to help clarify an argument or assert a position," states Scott Brown in the preface to "A View From the Campidoglio: Selected Essays 1953-1984" (by Robert Venturi and Denise Scott Brown, Harper & Row, 154 pages, $25), to be published next month. "For this reason they have an element of urgency, like letters from a battlefield."

"An almost unsuccessful practice," "letters from a battlefield" -- the phrases fairly teem with resentment against the unforgiving hostility with which their words and works were greeted in the early years.

For more than a decade after his first designs began hitting the architectural press in the early 1960s, and after the 1967 publication of his important book, "Complexity and Contradiction in Architecture," Venturi and his associates were treated as dangerous pariahs not only by major corporate and public clients of architecture but also by many architects and critics. As recently as 1976 members of the American Institute of Architects' (AIA)College of Fellows, an honorary body that includes any number of modest talents, refused entrance to Venturi when his name was put to a vote.

Ah, but sweet vindication was not long in coming. The Fellows' rebuff was rectified shortly thereafter and professional honors, as well as commissions, have since mounted. At the AIA convention next month in San Francisco, Venturi, Scott Brown and John Rauch (who joined Venturi in 1964 and is credited with being the best manager in the firm) will receive the organization's 1985 Firm Award in recognition of their "collaborative practice, which has so profoundly influenced the direction of modern architecture and urbanism."

More importantly, in a Harvard lecture three years ago Venturi was able to claim with absolute self-assurance that many of the principles he espoused in "Complexity and Contradiction" and in the even more resented "Learning From Las Vegas" (a collaborative effort with Scott Brown, Steven Izenour and a handful of Yale architecture students) "are now accepted wisdom." $"I am for complexity and contradiction in architecture . . . I like elements which are hybrid rather than 'pure,' compromising rather than 'clean,' distorted rather than 'straightforward,' ambiguous rather than 'articulated,' perverse as well as impersonal, boring as well as 'interesting,' conventional rather than 'designed,' accommodating rather than excluding, redundant rather than simple, vestigial as well as innovating, inconsistent and equivocal rather than direct and clear. I am for messy vitality over obvious unity . . . "

These trenchant thoughts from the so-called "Gentle Manifesto" that comprised the first, short chapter of "Complexity and Contradiction" were words of war upon orthodox Modernist architectural practice. They were received as such by outraged practitioners. "Learning From Las Vegas," with its now-famous celebration of "ugly and ordinary over heroic and original" architecture, drew even more blood, and more fire.

Venturi and, as the new collection of essays demonstrates, Scott Brown were formidable polemicists, intellectual wise guys whose brilliance was abrasive. But the main reason their words aroused such ire was much less a matter of style than of substance: In many, many ways they were right.

They attacked Modernist architecture at a time when it ruled the Western world, and when it had ossified into a set of safe formulaic practices that, if it occasionally could be transcended (as in the East Building of the National Gallery of Art), far more frequently produced hapless "unique" and "original" bombs (such as the FBI building or, on a lower, more pervasive level, the rebuilt K Street area in the eastern segment of downtown D.C.).

Venturi's body of thought, and that of Scott Brown and Izenour, is not easy. To the contrary, it is complex and rich in texture, shooting off in brilliant trails that less sure-footed souls, with reason, hesitate to follow. Venturi's recent insistence, for example, that applied symbolic ornament or all-over pattern are imperative in today's architectural-technological conditions could be a cul-de-sac from which less talented followers might never re-emerge.

But the impassioned polemics of Venturi and his close associates have had tremendous, liberating effects in the real world where buildings get built, even if the master himself, in that Harvard lecture (reproduced as the final essay in "A View From the Campidoglio"), disclaimed many of the efforts of his stylistic, "postmodern" progeny.

These writings helped pave the way for today's enlivened, pluralistic architectural production, helped to place architecture in line with historic preservation, stimulated the welcome reintroduction of historical architectural forms, encouraged interest in our more modest (if prevalent) architectural environments such as the commercial strip and Main Street, helped mightily to reduce yesterday's architectural "God complex" and, most of all, forwarded the important idea of incremental and evolutionary rather than total and revolutionary change in our built environments.

Underlying the polemics and the puns, the wit and the obvious delight in the fray, the twists and turns of irony and contradiction, there is a basic consistency of thought. More than any other person, Venturi can be called the father of contextual architecture, which is far and away the healthiest architectural idea of the last quarter century.

"The architect has a responsibility toward the landscape which he can subtly change or impair . . . the introduction of any new building will change the character of all the other elements in a scene," Venturi wrote when he was 24, in his master's thesis at Princeton. "Architecture can be many things, but it should be appropriate," he said three years ago. Not so many years ago it was fairly easy for some to dismiss the Venturi firm's architectural production while acknowledging, perhaps begrudgingly, its theoretical contributions. In part this was due to lingering resentment over the polemics, in part due to the apparent ordinariness of a few of the early designs, and in part to the fact that the firm didn't build much besides those "little houses."

It's not easy now. Many of the houses and even their details, such as overhanging eaves, extra-large double-hung sash windows asymmetrically placed, gables with eyebrow or circular windows, and so on, have been paid the sincerest form of flattery by other architects. Yesterday's Venturi shockers have become today's cliche's. Early works, such as his mother's house (the Vanna Venturi house, 1962) in Chestnut Hill, Pa., or the Guild House apartment building for the elderly in Philadelphia (1960-63), today have "architecture students like other places have mice," as one writer pointed out.

More importantly, the scope of work done by the Venturi firm gradually broadened during the 1970s, so there is a lot more to go on. Chief among the accomplishments are urban planning, urban design schemes such as the award-winning program proposing preservation with some appropriate, if rather slight, changes for the Art Deco district of Miami Beach, and big-scale public spaces such as the incredibly fetching underground museum and "ghost house" for Benjamin Franklin Court in Philadelphia.

Western Plaza on Pennsylvania Avenue in Washington is a triumph, too, although a sadly uncompleted one. I remain convinced that, should it ever be built as conceived, with three differently scaled elements above its richly inscribed table-top surface (high "framing" pylons, appropriately placed sculptural "models" of the Capitol and the White House, and scattered free-standing sculptures), it would become one of the world's great urban open spaces.

Venturi by now has proven himself a master of such spaces. Should the waterfront parks for the Westway project along the Hudson River in New York be built as he designed them, they will do much in the long run to remove the sting from at least the buried parts of the controversial road. They will give back to the city important portions of its waterfront in the kind of spacious, commodious, elegant parks that not so long ago we thought of strictly as things of the past.

"It used to be that a sure way to distinguish great architects was through the consistency and originality of their work," Venturi says, "but we say now that the sign of good architects is that all of their buildings look different."

This "freedom from consistency" is apparent in many recent buildings by the firm. There are structures, such as the economical Best Products Showroom (1979) in a Philadelphia suburb, with its colorful allover pattern of Warhol-like flower decoration, that look in photographs and drawings to be perfect for their settings. There are others, such as the Institute for Scientific Information (1978) in Philadelphia, with its emphatic all-over grid pattern sheathing an otherwise nondescript office box, that don't do much more than demonstrate a theory. And there are those, such as Gordon Wu Hall at Princeton (1981), that are at once ordinary and extraordinary, plain and fancy, modest and outstanding, just as Venturi often has suggested our buildings should be.

But many of the more audacious, interesting, or even boring buildings are not yet begun or are unfinished. There are modest suburban office buildings, whole suburban office parks, art museums in Austin and Seattle, a large laboratory at Princeton, a hands-on children's exhibition center at the Philadelphia Zoo, and two huge, patterned buildings -- "decorated sheds" and then some, to use Venturi's famous definition -- for Baghdad (stalled by the Iran-Iraq war).

It's too early to judge these buildings, of course, but this list alone practically assures that controversy will continue to follow where Venturi and his firm lead. Readers of "Complexity and Contradiction" who realized that, theory aside, its author was inescapably, brilliantly and tough-mindedly in love with buildings -- their history, their structure and above all their meanings -- will find it thoroughly fitting that future "Venturi arguments" will focus much more upon the buildings than on the words.