Almost exactly 20 years ago, the thirty-something Prince of Wales and his dazzling young wife made their first official trip to the United States, and America went all wobbly-kneed. Diana was the Intergalactic It Girl dancing at the White House with John Travolta. And Charles, after a lifetime of ponies and palaces and Mummy dressing him in silly pants, seemed suddenly hip.

This week, a graying Prince Charles arrives again, this time with his second wife, a woman as private as Diana was public, as country as she was city, granite to her diamonds. Camilla Parker Bowles, who became the Duchess of Cornwall when she married Charles in a small civil ceremony in April, has until now been carefully low profile in Britain. She favors boots, preferably muddy. If she has met Bono, the photos have not been in the papers. She is president of an association that fights osteoporosis, which afflicted her mother and grandmother, and she is passionate about good bone health.

She is Charles's comfort and companion, and finally his wife, after decades of being his confidante -- and oh-so-famously, his adulterous paramour -- since they first met in 1970. She is his friend. And she is his age.

Jonathan Dimbleby, the prince's biographer and a noted British broadcaster, said the royal couple's trip to the United States, which starts Tuesday at Ground Zero in Manhattan, will give Americans a chance to see firsthand the new and more sedate reality of Charles's life as Britain's king-in-waiting.

"It will be a much quieter experience," Dimbleby said.

It will also give the former colony a flesh-and-blue-blood look at a royal bride whose fairy tale has been anything but.

The duchess has no speeches -- or official public utterances of any kind -- scheduled on the seven-day trip to New York, Washington and San Francisco. She mainly will play companion to Charles at events as diverse as a black-tie dinner in the early-to-bed Bush White House to a production of "Beach Blanket Babylon" in harder-partying San Francisco.

The royal spin machine has been ratcheting up the duchess's profile in the past week to prepare for her big coming-out party among the coffee-swilling colonists. At a state dinner for the Norwegian monarch, she appeared for the first time publicly wearing a diamond tiara, a headpiece with roughly the same assessed value as Maine. The sparkly photos in all the newspapers were accompanied by stories fawning over Camilla's new role as a style trendsetter -- in a remarkable display of media hypnosis by Charles's image-meisters.

The duchess will certainly be front and center on her upcoming trip, and another public appearance last Sunday also hinted at the way she might conduct herself among the Yanks. At a service at St. Paul's Cathedral marking the 200th anniversary of Britain's great naval victory at Trafalgar, she was smiling, charming, confident and largely silent -- big image, small verbiage. The duchess walked slowly down the long church aisle -- the same one Charles and Diana walked down on their wedding day in 1981 -- wearing an elegant aqua-blue velvet dress and matching hat, her prince at her side.

Jackie Holloway was there, looking jolly well pleased.

"It was sad his marriage to Diana broke down," said Holloway, 56, quickly adding that the new couple made a lovely pair.

Still, said her friend Shirley Roberson, 49, it would be a mistake to make Camilla queen.

"That was what Diana was to be," she said in a 'nuff-said sort of way. She said she hoped Camilla would end up as a sort of "first spouse" without becoming queen, the way Queen Elizabeth II's husband, Prince Philip, is Duke of Edinburgh and not king.

For the record, Paddy Harverson, the Prince of Wales's chief spokesman, said British law states that the wife of a British king is always technically the queen, although the husband of a queen is not automatically king. But Harverson said Camilla has chosen not to assume the title, opting instead to be known as the princess consort -- a title that sounds perfectly reasonable to aristocratic ears but slightly naughty to the rest of us.

Harverson also stressed that Charles would become king upon the death of his mother and not before. He dismissed as "nonsense" speculation that the queen might step aside for Charles to ascend to the throne, or that Charles would decline the throne and let it pass to his older son, Prince William.

That kind of rumor is about as wild as things have gotten lately for the House of Windsor. These have been quiet days -- and therefore good days -- for a family that craves peace and decorum but often seems to find a whoopee cushion on its throne.

The queen will turn 80 in April, and she and Prince Philip have been all smiles and little waves in these cool fall days, when all the sex and scandal seems to be coming from the world of politics, not the palace. Royal aunts and uncles and cousins are behaving themselves. No one under the royal umbrella is divorcing, writing tattletale books or stomping their expensive shoes on the parquet floor and crying, "Poor me!"

Both of Charles and Diana's sons, William and Harry, have emerged as good citizens and are enrolled at Sandhurst military academy.

William, 23, graduated from Scotland's St. Andrews University in June. There he met a girlfriend, Kate Middleton, a proper-seeming young lady whose lawyers recently warned the media to mind their manners. William has begun to undertake solo royal duties, including a trip to New Zealand, and several work-experience placements, including joining a mountain-rescue team, working at an international financial institution and learning about land management on a country estate.

Little brother Harry has been at Sandhurst since May. After creating an uproar when he appeared in a Nazi costume at a party earlier this year, Harry recently gave a rare television interview on the occasion of his 21st birthday. He said he was delighted that Camilla makes his father so happy and does not think of her as his "wicked stepmother."

Then there is Charles, who turns 57 in a couple of weeks and seems to be a sort of royal barometer. For at least a decade, Charles's private life was a drag on the family. For a while it seemed that everyone who ever washed an argyle sock for Charles was writing a book. The queen's face was beginning to appear permanently puckered.

Not anymore. Charles seems at his most content these days, all ruddy-cheeked and good cheer in the cotton and wool and leather of princedom.

Dimbleby, who attended the couple's wedding reception at Windsor Castle, described Charles as "at ease with the world, and he's with a woman he loves."

"I think there's a real love there that makes people smile when they observe it," he said. "She is good at pulling him down if he indulges in pomposities. She is very much grounded when he's got his head in the clouds. But she's very much in awe of him as well."

In a rare BBC television interview recently, Charles was filmed at his farm in Gloucestershire in southwest England looking every bit the county gent petting pigs and driving a muddy Land Rover. He spoke about his worry about bird flu and the effects it might have on poultry farmers, particularly those who follow his organic, free-range mantra.

"I feel so deeply for the poor old poultry farmers in this country," the prince lamented. "So many people you see have struggled away to get their chickens outside for all the right reasons. Then to find suddenly that they might have to shut them all up, I mean it's very, very worrying. . . . You can only pray."

He was even more passionate about climate change, calling it the "greatest challenge to face man" and urging world leaders to treat it with a "far greater degree of priority" -- a statement sure to endear him to the White House, which rates climate change roughly on par with Mr. Bean as a threat to mankind.

The Charlesian calm seems to trace to the wedding day. Before then, the storyline in the British press rarely varied: Charles was a bad husband and a lousy father -- a fruitcake who talks to trees. Camilla was a frumpy home-wrecker. The queen disapproved of the whole thing.

Then they married. The queen gave a warm toast -- they laughed, they cried. And except for a bit of cattiness about Camilla's wedding day hat (which did, to be honest, look a bit like a duck blind), the tone of public discourse changed. A truce seemed to be declared in the press, and the British public seemed to accept the idea of a widower and a divorcee finding each other in middle age and just getting on with it. Nobody forgot Diana, but they seemed willing to let Charles move on, as long as he does so quietly.

"The wedding acted as a soothing balm on the public. The tide turned because of the innate decency of people. I think they see that she's decent and he's happy," Dimbleby said. "The British public welcome their marriage, but they don't want it or her to be, as it were, in their face."

Since the wedding, Charles has made few appearances not related to the network of charities he runs, which raised more than $180 million last year. Often mocked for what many here see as his emphasis on goofy New Age pursuits, Charles has maintained a steady and serious advocacy for education, organic farming, the environment and more human-scale urban development -- which are reflected in his agenda in the United States. The trip's 21 public engagements include visits to organic farms in Marin County, north of San Francisco, and the National Building Museum in Washington.

It will be the prince's first official visit to the United States since 1994, although he has been back briefly in a personal capacity three times, most recently for the June 2004 funeral of Ronald Reagan. Harverson said the prince makes two official overseas trips a year and the destinations are chosen by the Foreign Office, depending on where they feel Charles can best serve British interests.

Harverson said the U.S. trip was originally scheduled for the fall of 2001 but was postponed because of the 9/11 terror attacks. He said the Iraq war, in which the United States and Britain are the key players, had nothing to do with timing of the prince's visit. "This is simply to reinforce the especially close relationship between the two nations and essentially fly the flag of Britain in America," Harverson said. There is more than a little speculation here that Charles is also trying to woo back anglophile U.S. tourists who still may be spooked by last summer's bomb attacks in London.

The prince and the duchess will meet President Bush and the first lady at the White House twice on Wednesday, first for a private family lunch and then the black-tie dinner -- a rare double-header. In a remarkable reversal, the prince known for raging self-doubt suddenly finds himself far more comfortable in his skin than a president whose famously unwavering self-assurance seems suddenly in doubt in Washington's current political atmosphere, which resembles the inside of an industrial wood-chipper.

Bush and Windsor (Charles's surname -- although his children's last name is officially Wales) have much in common. They were born two years apart, both into families of great privilege with strong-minded mothers, boys who in their youth didn't always seem sure they wanted the keys to the manor. They have both endured relentless poundings from the media. But there the similarities end between the embattled Texas rancher and the English country squire who has never seemed more relaxed.

John Lloyd, editor of the Financial Times magazine, said Charles and Camilla are trying to adjust the monarchy's role in public life to keep it relevant but protect it from too much unwanted attention.

By the time Charles becomes king, Lloyd said, most Britons will have no firsthand memory of the royal family's stoic leadership during the bombings of London in World War II. He said Charles won't have the bedrock support of that grateful generation, and he is "too odd and too eccentric to really count on much affection" from younger people.

"He will shift down several gears and try to keep the monarchy at a low key," Lloyd said. "And Camilla is very sensible; she knows the score."

Graham Smith of Republic, a group that wants to replace the monarchy with an elected head of state, said the British public is increasingly ambivalent about the monarchy. "Fifty years ago, we were brought up to believe that we should love and honor the royal family," he said. "They've now been downgraded to nothing more than just another celebrity family. They're just ordinary people now, nothing special. And people are asking why they should be in such a privileged position."

Dimbleby said privilege comes at a cost, including high-profile official trips to a nation still obsessed with Diana, where the new Duchess of Cornwall will be endlessly televised, scrutinized and measured against a memory.

"She's as tough as old boots," Dimbleby said. "She can take this."

Britain's Prince Charles and Camilla, Duchess of Cornwall, emerge from St. Paul's Cathedral in London last Sunday. Prince Charles and Camilla after their wedding in April, with William and Harry. The younger prince says he does not think of her as his "wicked stepmother." Below, Camilla, Prince Philip, left, and Queen Elizabeth II before a banquet for Norway's royals in Buckingham Palace on Tuesday.