Frank O. Gehry, the late 20th century's most daring architect, was standing reluctantly on the highest balcony of the National Building Museum's atrium. He steered clear of the railing. He sought refuge in a tiny dark alcove.

"I don't like heights," he said softly.

Gehry's buildings are as bold as any on the planet. His titanium-clad Guggenheim Museum Bilbao has been hailed as a new architecture for a brave millennium. His vision for the Corcoran Gallery of Art could bring those undulating waves of metal, or perhaps stone, to this Federal-style city.

But the architect displayed few heroic notions about himself. He said he was feeling "insecure." As soon as his photograph was taken, he slipped into an elevator and disappeared.

Gehry was in town Monday to show what he had accomplished in the five years since he designed Bilbao. More than 1,600 of Washington's design faithful--the largest audience in Museum memory for an architecture lecture--flocked to the building's Great Hall to see him. While waiting, they snapped up 300-plus copies of his new book, "Gehry Talks" (Rizzoli, 300 pp., $65).

"I'm overwhelmed," Gehry said in greeting them. "This is staggering."

He showed them his latest curves, in brick for a Cincinnati medical school, in slumped glass for the walls of Conde Nast's cafeteria in New York. Those transparent separations for power-lunch tables are being crafted in Italy; the clients flew over for a meal to approve the mock-up.

"We won't be doing anything like this at the Corcoran," he interjected.

There was a major project for the Massachusetts Institute of Technology, a glowing steel band shell for Chicago's lakefront, the "swoopy" music museum for Seattle. Tame by comparison, the Corcoran addition was still evolving in Gehry's head.

He drew "some parallels to working in Washington" with Berlin, where he has designed an acceptably squarish bank building "on a holy piece of land" next to the Brandenburg Gate. Friends warned him that too many controls there would lead to a cop-out design, he said. "I responded as creatively as I could."

The German building may appear conservative from the street, but an inventive atrium hides within. A conference center seems to float there like a bubble of steel lined cozily with wood.

"My contribution is a new way of looking at architecture that's not about fussy detailing," he explained in a conversation before the event. "It's about celebrating imperfection, celebrating human frailty."

Since the Guggenheim, Gehry, who cuts an elfin, silver-haired figure at 70, has become something of a celebrity. In Bilbao, people try to touch him; at airports, he's stopped for autographs. Susan Henshaw Jones, president of the National Building Museum, introduced him as a "megastar." At least one pundit has likened him to Frank Lloyd Wright.

"I plod along," Gehry insisted. When pressed, he acknowledged that he had given the Wright comparison some thought, but decided that his body of work does not yet measure up.

The book provides 33 of those works, most shaped like ribbons of steel and tumbling piles of boxes. The lone skyscraper is an unrealized project for Warner Bros. at Times Square. The 350 photographs and drawings include his bentwood chairs for Knoll, but not the fish-handled teakettle for Alessi, the Italian housewares maker. Gehry was happy to sketch one on a napkin. "I loved it, but it didn't sell," he remarked. He has declined other offers to market products with his name.

Gehry believes he can overcome critics of his designs by bringing people into his thought process. To sell Prague on a building of dancing towers, since dubbed "Fred and Ginger," he showed opponents the series of models through which his visions evolved. "Some clients don't understand the process," he says in the book. "What I'm telling them is, watch it, get involved, understand that I'm not stopping here."

It doesn't always result in a building. Gehry tried for a decade to design a house for a private client. He is startlingly frank in describing the saga, in which the projected cost soared to $65 million, the size to 42,000 square feet before the commission faltered. Each room resulted in a model so artistic that galleries have sought to offer them as sculpture. Gehry believes the client, philanthropist and insurance executive Peter Lewis, never needed the house in the first place. Remarkably, client and architect still are dining together.

Rather than a failure, Gehry calls the engagement his MacArthur grant. The creativity expended on the Lewis house provided the spark for Bilbao.

"Once you taste blood, you're not going to give it up," he says in the book. "I don't know where it can go. How wiggly can you get and still make a building?"

Some of the new projects barely wiggle at all. If they seemed destined to make fewer headlines than Bilbao, a question remains: Do you need an encore if you've already made history?

"Bilbao shows how to fit a building into a city without destroying the fabric of the city," Gehry reflected this week. "It was a big turnaround in terms of people accepting my work. I don't know whether you get another chance. Opportunity comes along once in a lifetime."