Ashok Bajaj knows a lot about Karen Shaw Petrou.

He knows, for instance, that Petrou - a prominent financial consultant and lecture circuit wise-woman - navigates Washington with a seeing-eye dog. He knows that she likes Hendrick's gin. He knows that she and her husband, Basil, are prone to sip Bergstrom Old Stones Chardonnay.

Most important, he knows that Petrou has eaten at his Cleveland Park restaurant - the once separate, but now joined Ardeo + Bardeo - at least 203 times in the past five years. All that information, and more, resides in the computer that Bajaj keeps behind the desk in his bland-as-toasted-white-bread Penn Quarter office.

So, it was with some distress that Bajaj observed about a year ago that the Petrous - Olympian patrons that they had become - gradually stopped going to the restaurant. When he finally spotted them back, he asked why they'd forsaken him, and after some hesitation and considerable hemming and hawing, they told him.

"We thought the restaurant had gotten tired," Karen Petrou recalls telling him. She wanted more vegetarian dishes and more appealing fish. And not only that: The couple had taken up with another restaurant. (The Petrous, being discreet sorts, prefer not to mention the place that won their affections, but Bajaj blurts it out when I ask him later: It was BlackSalt, the Palisades neighborhood hangout.)

Like a spurned lover, Bajaj's first reaction was disbelief and confusion. "We have the same fish supplier," he protested. But he kept listening, and what they told him dovetailed with his own concerns that the restaurant needed a makeover. In November, more than $1 million later, Bajaj unveiled a redesigned, rethought, reconfigured restaurant. Louder, younger, more fun. The Petrous approved, and they resumed their metronomic dinner stops on the way home to Forest Hills from their Capitol Hill offices.

And so it goes in the Empire of Ashok, a land of power dining and power appeasement that encompasses six see-and-be-seen restaurants, each with a distinct menu and vibe, but a similar Ashok-ian polish: Ardeo + Bardeo, the Oval Room, 701, the Bombay Club, Rasika and Bibiana Osteria-Enoteca. A seventh is on its way - Bajaj hasn't made any announcements, but in this city where secrets always leak, savvy insiders are already gossiping about his plans for an Indian restaurant near the Ritz-Carlton in the West End.

The staggering breadth of Bajaj's claim on Washington business-lunching gives him a kind of power all his own: to decide what goes into the stomachs of the people who run the country (or think they do). But the formula is more complex than simply attracting boldface names; he also understands how to feed the people who feed off the government - the highly scheduled and highly compensated bedrock of consultants, lobbyists and lawyers who constitute permanent Washington. They may go unrecognized outside the Beltway, but they get treated like Big Men (or Women) on Campus inside the giant fraternity-sorority system that is the nation's capital.

While Washington hot spots come and go, Bajaj's endurance 21 years after opening the Bombay Club, the first of his restaurants, derives in part from his ability to be a shape-shifter. That '90s-style caviar bar at 701? Gone, now that excess is considered excessive. Yet sometimes Bajaj wins by being a dug-in upholder of tradition. That tandoori salmon you loved at Bombay Club during the Clinton administration? In-the-know eaters can still order it, hip to the kitchen's willingness to prepare it for them even though it's not on the printed menu.

"I call him the maharajah of Washington power dining," says Lyndon Boozer, a telecommunications lobbyist whose mother was President Lyndon B. Johnson's personal secretary.

Bajaj recruits talented chefs. For Rasika, he snagged Vikram Sunderam - a fish chutneywala- and cauliflower bezule-conjuring magician - from London's celebrated Bombay Brasserie. But chefs come and go, too; the longest tenure at one of his restaurants was 10 years, and most stay for much less. Even though his chefs can achieve a measure of stardom, it is the owner who is the empire's face. He is "Spider-Man," in the words of some staff and patrons. They marvel at his time- and space-defying ability to appear seemingly out of nowhere on his nightly circuits of the empire. He visits all six restaurants every night, plotting his night wandering to match the ebbs and flows, and A-list juice, at each of his possessions.

He can also be the realm's equivalent of Don King, a nonstop promoter and spectacularly prolific - though curiously unannoying - name-dropper. In a town with more than its share of insufferable prestige accumulators, Bajaj manages to hype his restaurants and his guest lists in an endearing way. Rather than coming off as bragging, his enthusing has the effect of drawing his guests deeper into his circle - they are members of his club, and feel privileged to share in his wonder.

"This is such a small town," he confides on the phone one afternoon, offering that he'd been talking the day before with New York Times columnist Maureen Dowd. A few nights later, at Ardeo + Bardeo, he's whispering that Cokie Roberts, ensconced at a nearby booth with Gloria Borger, has been to three of his restaurants in three days. Another time, over lunch at 701, he shares that Diane Sawyer dined at the Bombay Club the night before, while a winter storm outside brought traffic to a halt.

At the Bombay Club's bar one evening, he declares, "Society dines here."

"I can give you," he says, clipping a sentence before finishing it, leaving you to fill in the blanks. In this case, the rest of the thought could be something like: "a list of names that will blow your mind!"

"Madeleine Albright. Hillary Clinton," he says, his voice inflected with the musical notes of his boyhood days in India. "President Bush senior. President Clinton. John Kerry. Nelson Mandela."

He's rolling now.

"Prime ministers. Presidents. The Salahis. I mean, it's a Who's Who."

And there's more.

"Hollywood? Harrison Ford. Stevie Wonder. God, I can give you - Condoleezza Rice. Okay, Bruce Willis. Demi Moore. What is the Australian actor who got in trouble?"

"Mel Gibson?" I answer.

"Yes," he says emphatically. "Mel Gibson."

Ashok Bajaj doesn't cook. Ever. In the refrigerator of his Foxhall Crescent home, he's got a bottle of champagne, a few beers, some white wine.

"What else?" he asks himself. He likes asking himself questions. Then answering them.

"Okay, orange marmalade."

Bajaj (his first name, by the way, is pronounced Aw-shoke, not Aw-shook) is a man of average height and deferential manners, practiced as he is in the art of fading into the background. His hair is a bit thinner now and his thick black mustache is gone, but he leaves few clues about the passing of time. Even close friends and longtime regulars at his restaurants have no idea how old he is, which is understandable because he pointedly keeps his age a secret, a habit that has become such an irresistible quirk of his persona that it has provoked no small amount of speculation.

He is a man of self-prescribed and meticulously observed rules. He drives a luscious convertible Mercedes-Benz CLK500, but the top must never be put down during the week, because that wouldn't appear professional. He must find 10 minutes a day to meditate - his aide, Pat Minter, who has worked with him for two decades, occasionally pops into his office only to discover that her boss has transported his mind far, far away.

Bajaj dated the same woman for many years, but is single now. When he goes out on a date, his rules dictate that he must never go to his own restaurants - too showy. A handful of his most frequent diners tend to take an aspirational interest in such matters, hoping that their loving host will find love himself. Fred Hochberg, the big-time political fundraiser and head of the Export-Import Bank of the United States, invited Bajaj to a Valentine's Day dinner this year with a guest list consisting largely of single friends. Bajaj, alas, declined, saying he needs to attend to the already-coupled crowds that will fill his restaurants. Bajaj is always dating, Hochberg says, but "it's always 'sort of' " dating. (Hochberg has stopped to chat after arriving from across the street, where he attended a speech delivered by President Obama, to have lunch with former D.C. mayor Adrian Fenty - just another day at the Oval Room.)

Hochberg compares Bajaj's appeal to that of the famed New York restaurateur Danny Meyer, whose presence and personality infuse Manhattan buzz-hubs such as Union Square Cafe and Eleven Madison Park. "The tricky thing," Hochberg says, "is once you start that, people expect to see you." Bajaj generally opts for the quick tableside drop-by so he's not intruding and so he can dispense TLC to more guests per hour. "I'm the icing on the cake," he says.

Bajaj blends in among the lobbyists and lawyers and government head-turners who populate his five downtown establishments. Their expensive but safe tastes are his expensive but safe tastes. One day at lunch at 701, he inhabits a dark Ermenegildo Zegna suit and a meticulously knotted tie. A few nights later over dinner at Bibiana, he's in a dark Giorgio Armani ensemble and a perfectly knotted tie.

It prompts some questions.

Own any T-shirts?

"Polo shirts? Yes," he says one night as he steers the Mercedes down Connecticut Avenue between stops at Ardeo + Bardeo and the Oval Room.

Not the question. What about T-shirts?

"Like without a collar?" he says, as if the thought of such a garment is utterly unfathomable. "Oh, no."

Later that night, over dinner at Bibiana, I can't resist asking him how many suits he owns. At first, he won't say.

"Twenty?" Bajaj smiles coyly and points his thumb upward.

"Thirty?" More upward thrusts.

This goes on for awhile until Bajaj - a man who can be flamboyantly specific one moment and just as flamboyantly vague the next - settles on 50. They are, he says, "his uniform."

But are they all dark? He needs to think about that. Finally, after a long pause, he allows that he might have something that's not black or dark blue.

A few days later, he tracks me down at lunch with a friend at Rasika. He's wearing light brown.

"I wore it," he says, "for you."

Bajaj was born (at an undefined moment in time) in New Delhi to a family that had some means, but wasn't wealthy. He traveled to India frequently to visit his ailing father, who died 21/2 years ago. Since then, he says, he hasn't been able to bring himself to return.

He first left India in his early 20s, he says, looking to explore the world, and learned the hospitality business in London and Sydney. The details of how he came to settle in Washington are as arrestingly imprecise as the matter of his age. "Suggestions were made," he says, leaving it at that.

There's nothing sinister about Bajaj's coming-to-America story, but it deviates a bit from the narrative of him as the sole master of his universe. It's mostly forgotten to time, but Bajaj opened the Bombay Club in 1989 with a partner, a wealthy Australian man named Nelson Blanks.

Bajaj is protective of the provenance of the Bombay Club's culinary and atmospheric appeal, which channels a colonial-era langor, or as lobbyist Boozer puts it, feels like "walking into the movie 'Casablanca.' "

Bajaj says Blanks "was never in the restaurant business. I was in the restaurant business. He was in the real estate business." The partnership soured after about a year and a half, he says, and Bajaj ended up with the Bombay Club. "It was a bad breakup then," Bajaj says. "Since then, we've been okay."

And since then, it's been all Ashok. In a business that often rests atop tangled piles of quarreling investors, each with ownership percentages parceled out like shares in a mutual fund or points in a Hollywood production, Bajaj stands apart by standing alone. He says running a restaurant is like "theater," and he casts the staff like a producer casts a movie - exactly to type. Irfan, the Bombay Club maitre d' and manager who has worked at the restaurant for two decades, oozes old-world charm with a hint of mystery. Chelsea, the general manager at 701, could easily play the part of a young partner at a law firm. Francesco, the wine director at Bibiana, is Italian and oh-so-Euro-chic in close-fitting suits and hipster glasses - custom-made by a friend in Italy, he says one night.

The impresario role is played by Bajaj. He likes to be in control of almost everything. One night, he asks me where I'd like to join him for dinner. "Anyplace," he says. "You choose."

I suggest the Oval Room.

Bajaj considers the choice for a few moments, then returns to the subject minutes later in the car, and then after much exceedingly genial and diplomatic this-ing and that-ing, he says we're going to eat at . . . Bibiana. It's a seesaw familiar to those who work with him. "How much freedom do the chefs have?" Bajaj says. "One hundred percent."

"But I give them guidance," he adds. "Chefs, he says, "can be crazy sometimes." (Bajaj, who is famously demanding of his staff, volunteers that he yelled a lot at employees when he was in his 20s. But he seems to have lowered the volume considerably as the years go along.)

At Ardeo + Bardeo, I ask Tony Conte, the much-respected chef who oversees the kitchens in all of Bajaj's non-Indian restaurants, whether he's experienced this "you decide, I decide" dynamic. Conte smiles, an expression more of affection than exasperation. "A little," he says.

Bajaj has already tinkered with the thermostat, and while I'm talking to Conte, he fiddles with the lighting. "Did you turn down the lights?" the new manager, Dave Pressley, asks Bajaj. "We can't see the tabs," a reference to the restaurant's order slips.

Bajaj asks us both what we think. Varying levels of mildly contrary opinion tumble out. But the lights stay down. "For me, I walk in from the outside and - " he says, chopping another sentence and placing his open right hand over his face to mimic being blasted with light. This is a modification of his sentence-fragmenting tendency: the gesture to replace words.

Finding the right fit for the times sometimes generates grumbles. At 701, he recently spent $800,000 on a makeover that sprinkled a bit of glimmer - a patterned glass wall and an updated lounge with more hard surfaces - amid the white tablecloths. Some of the regulars found this disconcerting, and Bajaj, reflexively, is working on appeasing them. John O'Donnell, a lobbyist and frequent diner, told him that the round tables were too small and the lounge didn't feel "as friendly" as before, Bajaj says. "Johnny," as Bajaj calls him, "wanted a little bit of a settee. That's fine, I'll give him what he wants." Tables measuring 24 inches will soon replaced the 16-inchers.

Keeping the regular eaters happy is essential in a competitive restaurant town, though Bajaj says he prefers to complement existing restaurants - by finding a niche different than theirs - rather than engaging in full-frontal combat. Bajaj wonders aloud about "who would be my competition" at Bibiana, which opened in September 2009. "Tosca?" He's referring to Ristorante Tosca, an established favorite of Washington's elite. "Tosca is white-tablecloth. Very formal. At Bibiana, you come in, it's less formal. So you can be yourself."

Cross-pollination is not uncommon, even among the most habitual of grazing lobbyists. There's plenty enough bonus money to spread the cheer. But, occasionally, there are outright defections. Friends of Nicholas Calio, a top presidential legislative adviser in both Bush administrations, say he migrated from Tosca to Bibiana amid the fallout over a September 2009 Washington Post piece about Tosca's popularity among lobbyists. The article noted that Calio, a Citigroup lobbyist at the time, could reliably be found getting VIP treatment at Tosca, entertaining over a bottle of red wine at his regular table in what was referred to as the restaurant's "TARP section" - the domain of lobbyists for bailed-out financial companies.

The optics weren't the greatest, and friends soon observed that Calio dumped his Tosca routine - loyalty for all those years of special attention apparently not being enough to keep him around. Not long after, he was spotted getting the "Hello, Mr. Calio!" treatment and enjoying a glass of wine over lunch in the more casual, but far from shabby, Bibiana, where he is now a frequent diner. Calio, recently named president and CEO of the Air Transport Association, did not respond to an interview request.

Calio's old boss, President George H.W. Bush, occupies a place of honor in Bajaj's world: An image of the restaurateur and the former president at the Oval Room resides on the wall in Bajaj's office hallway, one of only three framed photos hanging there. The other two show Bajaj at 701 with President Bill Clinton and at the Bombay Club with Hillary Clinton.

There is no such image of President Obama, who has supped at Blue Duck Tavern and Citronelle, among others, but has yet to make the scene in any of Bajaj's places since occupying the town's coolest oval room, the one at 1600 Pennsylvania Ave. Bajaj points out that Obama ate at the Bombay Club when he was a senator, that first lady Michelle Obama has been spotted at Rasika and that many Obama staffers eat at his restaurants. But the Big Get, the president, has eluded him - at least, for now.

"I'd love to have Obama," he says. "I told Valerie Jarrett. I told Rahm Emanuel."