Richard Ridley peers out the south window of his 10th-floor office directly into the searing light of a late winter afternoon. But he dows not see the somewhat tawdry dry mix of tourist joints, luncheonettes and wig shops below on 10th Street.

In mind's eye, the 42-year-old architect and planner envisions quite another city. He sees Washington as a vibrant mix of old and new: downtown buildings soaked with natural light from verdant interior courtyards. Housing folded into commercial areas keeping streets bustling and safe day and night.

"Wouldn't it be wonderful," he asked rhetorically, waving his hand in a broad stroke towards the window, "to live down here?"

But the native Californian is no feckless idealist. Rather, Ridley might be called a "public interest" architect, an "expert" witness on the side of the "little guys" at zoning hearings and other governmental forums, helping community organizations and others to counter the "experts" trotted out by land developers.

Ridley and his two associates, Jon Lourie, a 27-year-old Maryland native, and Rick Wieboldt, 29, who studied in New York City and Minneapolis, probably spend as much time before zoning boards as at their drafting boards. Like public interest lawyers, they also provide pro bono or cut-rate services to community groups.

In a field known for its corporate sameness, Ridley is still applying the lessons he learned at the University of California at Berkeley in the politically charged '60s--and prospering in the pragmatic '80s. His clients have included neighborhood activists and public defenders as well as developers and homeowners. And in 15 years here he has fought to close an overcrowded jail, mediated multimillion-dollar development disputes and leaped into preservation frays.

A medium-sized man with bushy brown hair and a craggy yet youthful face, Ridley sat recently with Wieboldt and Lourie at an oblong butcher-block table in his pleasantly cluttered offices at 514 10th St. NW, converted from an industrial loft. Classical music seeped in through huge wall-mounted speakers as the three unwrapped pungent hero sandwiches and wrenched the caps off bottles of Molson Ale.

"The question is," Ridley began, "how do you get the best architecture to happen?" One answer, he says, is public participation: involve the users and neighbors of a proposed building in the design process.

Since 1978, his firm, Richard Ridley & Associates, has put that concept to work to resolve a series of particularly sensitive conflicts: the development of the last great residential estates of Northwest Washington. In the affluent Palisades, Cleveland Park and Spring Valley areas, neighborhood groups have hired Ridley in the hope of preserving these historic and park-like settings. He, in turn, has advised them to abandon obstructionist tactics and negotiate for the best possible development.

In 1978, Palisades citizens asked Ridley to analyze a plan by noted Washington designer Arthur Cotton Moore to build 170 luxury houses on 24 acres of the former Nelson Rockefeller estate on Foxhall Road. The $60 million project was proposed by the development company of Rozansky and Kay.

Ridley took the Moore drawings and made overlays showing exactly how many trees would be lost and how buildings on steep grades would cause erosion and damage the water table. Using his distinctive drawing style, a combination of cartooning and conventional drafting, he was able to convey the issue in enviromental as well as planning terms. Moore agreed to cut the number of houses to 120, and in 1979 the citizens and the developers signed an agreement approving the plan. It was the first time that such a local dispute was settled amicably--and out of court.

Ridley says it all points to a new spirit of cooperation among development adversaries. "The art of intimidation--screaming at public meetings--is on the wane," he said. "Developers are now saying, 'We know what you don't want. But what do you want?' In response these groups are getting more sophisticated."

"We go out and say we don't like it," said Kathleen Wood, vice president of Friends of Tregaron, a 14-acre Cleveland Park estate proposed for luxury town house development. "But Rich says, 'Well, you can accept this.' He's objective and has the larger interest of the city in mind."

"We're just a hired gun," Ridley said of his firm. "The public knows there's something wrong with a plan. But they can't articulate it. We can."

Ridley's objectivity has been praised by adversaries and clients alike. And it's difficult to get his adversaries to speak ill of him. ("No one can be mad at Rich," one said.) Yet he is caustic on the subject of many area developers, who he says "tend to pull their stock plan out of a drawer. They say, 'Well, it worked in Reston, so let's bring it downtown.' "

Steve Armington, an architect for Sasaki Associates Inc., a Watertown, Mass., firm that designed a proposed 63-unit housing development for the 13-acre Majorie Phillips estate on Foxhall Road, said that Ridley made the community group "realize that there was going to be some development and they should try to influence it rather than stop it."

Ridley compared the situation to the Georgetown waterfront, now dominated by dense condominium development that was bitterly opposed by residents: "Many felt that if there had been more cooperation there could have been smaller buildings that would have pleased the citizens more." He added that developers sometimes try to "trample obdurate or implacable opposition."

Ridley told of another developer who drove by a wooded site and "thought his high-rise buildings would look just fine there! Whatever happened to the Frank Lloyd Wright idea that you went to the site and sat on a rock? And you watched the sun go up, and you watched it go down."

It all points to a lack of pride among today's builders, he says. "It used to be that all buildings were named after their owners. Now the address becomes the name, like 1600 K Street."

And architects, he said, fall prey to what he terms "the one-half of one percent solution. They spend all their time solving zoning, economic and building-code problems. The real design time winds up being minuscule. But the design is what people respond to. And more often than not here, they call it a horrible building."

His views were forged in the politically charged atmosphere at Berkeley, where he first studied architecture in the early '60s. Ultimately, however, he "felt isolated from political change in the West" and continued his education at the Harvard Graduate School of Design.

In 1967 he moved to Washington to work in the local office of Skidmore, Owings and Merrill. He left in 1970 to become a partner in a new type of venture. It was a "public interest" architecture firm called October.

October didn't shake the world, but Ridley got an assignment that won him national recognition. In 1973 the D.C. Office of the Public Defender hired him to investigate allegedly brutal conditons at the old D.C. Jail. The public defender was suing the city to close the 103-year-old, 850-prisoner facility on Independence Avenue SE near the Armory.

Armed with a thermometer, drawing pad and camera, Ridley went to the jail. Conditions were indeed fetid. He found that pipes from a latrine leaked into pots on the mess hall stove. The jail was overpacked by at least 250 prisoners, many doubled up in 6-by-8-foot cells. The heating and cooling systems were so inadequate that even the guards complained. Other building code violations were abundant.

As part of his testimony in D.C. Superior Court, Ridley assembled an elaborate slide show. More dramatically, he presented a series of drawings that communicated the dilemma of overcrowding in the simplest terms.

The judge ordered the jail closed and part of it has been torn down. Progressive Architecture magazine recognized Ridley's role with an award in 1975. The same year October dissolved and Ridley went off to start his own firm.

Ridley has won the type of prestigious commissions that gain attention in interior design publications: condominium conversions, custom solar houses. He has converted several Georgetown houses into lush, live-in "bath houses" with hanging gardens and walkways suspended over swimming pools.

He spends his spare time devising uncommissioned drawings for projects like Metro Center "just to get people thinking about how that important site could be used." And he's preparing a brochure to get minority and low-income neighborhood groups involved in development issues.

The author is the assistant editor of Preservation News magazine.