Back in New York, Bloomberg frequently hosts small dinners at his five-story limestone townhouse in the East Seventies, which is handsomely decorated with a Fragonard sketch, eighteenth-century landscapes, and antique English furniture. What surprises guests is the eclectic array of New Yorkers invited and the often down-home fare: meat loaf and mashed potatoes, fried chicken, even burgers. "People love it," he says. "Everyone else is serving the same piece of salmon." A recent dinner-party guest list included Steve Forbes, a passel of Wall Street types, his daughter's riding instructor, and pollster Doug Schoen. "He loves putting people together," says Barbara Walters. "I sat between the basketball commissioner and someone from the Museum of Modern Art last time."

One signature touch at Bloomberg's dinners is unusual place cards: big vanilla cookies, baked with the guest's name and a personalized image (a tennis racquet; an alma mater crest), preferably the more obscure the better. When Harold Varmus, the Nobel Prize winner who now runs Memorial Sloan-Kettering, and his wife, Constance Casey, went to dinner at Bloomberg's earlier this year, Casey was astonished to see her terrier, Isabel, on her cookie. "My dog wasn't mentioned in any of the profiles of Harold," she says. "I still don't know how they found out." Bloomberg, with a grin, refuses to reveal his sources.

What he doesn't have these days is a steady girlfriend (or if he does, he's really, truly discreet). Late one night, Bloomberg admits that he's surprised to still be single. He presumed he'd remarry within a few years of his divorce and has come close once or twice; no, he won't name names, but he did have a close relationship with Broadway star Ann Reinking, and for years his friends were expecting him to tie the knot with Mary Jane Salk. Since breaking up with Salk, Bloomberg has enjoyed the perks of single-billionaire-hood, dating actress Marisa Berenson and last summer taking diva Diana Ross to dinner at BondSt, a date memorialized forever by the tabloids. "I was furious at that restaurant for calling the papers," he says. "I've never gone back there again."

In the political arena, without any record as an officeholder, he will be judged and defined in the upcoming campaign by his history as a CEO and, he hopes, by his commitment to charity. With 7,000 employees around the globe, he has developed a corporate culture with its own decided quirks: no titles, no private offices or executive dining rooms, endless free junk food and healthy snacks at the cheerful food court, aquariums as handsome wall dividers, well-paid workers (a Daily News reporter gleefully recalled that he tripled his salary when he joined the company last spring), and a no-exit clause: Anyone who quits to take another job cannot come back, ever.

After presiding over a well-paid high-tech white-collar staff with glossy resumes, he would certainly find it radically different to tackle an entrenched civil-service bureaucracy resistant to change. But he insists that some of his company innovations would be worth trying at Gracie Mansion, such as rotating key managers for a few weeks at a time so they can learn how the other half lives. He would also try to promote from within, as a morale-building exercise. "All of our top management has been grown from within the company," he says. "If people think they can move up, they work harder."

At the sleek black Bloomberg building on Park Avenue and 59th Street, the two policies raising the most eyebrows these days are the intense security (all staff members have to use an electronic badge to enter, and a computer logs their ins and outs) and a software program that blocks profanity and epithets from internal e-mail for staff and messages sent by clients via the Bloomberg terminals. Bloomberg's voice rises -- he's almost squeaking -- when I ask him about this policy. "It's our system, and I have a right to limit what goes over it," he says. "I don't think it's in our clients' interest to allow abusive language in a business context." Calming down, he then tells me that it's quite easy to subvert the program; all you have to do is put stars or spaces between the letters of swear words. When I ask if Bloomberg ever swears himself, he bursts out laughing: "Me, the man the Wall Street Journal referred to as 'the profane Michael Bloomberg,' to my mother's everlasting mortification?"

He admits he's tried to clean up his act in recent years -- he limits himself in front of me to the abbreviated "NFW," as in "no fucking way" -- but friends and colleagues acknowledge that he can be a salty guy, a true product of Wall Street's raunchy trading-desk culture. "He's a really bawdy guy, very funny," says a woman friend, "but you don't take 75 percent of what he says seriously; he just loves to get a rise out of women." Female staff report that he has a good record for promoting women and minorities and has never been accused of hitting on his employees, but he has made flip sexual comments that women have found offensive.

Last month, the Daily News rehashed the details of a 1997 sexual-harassment complaint against Bloomberg by former sales executive Sekiko Garrison, who charged that when she told him she was pregnant, he responded, "Kill it." He has denied, under oath, that he made this and other crude statements, but nonetheless he settled the case last spring, for a sum said to be less than six figures. The lawsuit wasn't news per se -- it had been mentioned before in the press -- but the specific charges taken from the original legal papers made headlines. "Mike expected people would dredge it up," says Bill Cunningham, a recently hired senior political adviser to Bloomberg, "which is why he took and passed a lie-detector test."

Bloomberg chooses his words carefully when he's asked about the sexual-harassment lawsuit and the press feeding frenzy after the Daily News story. "It was very hurtful," he says. "I am 100 percent convinced that this company and myself acted honorably." Why settle, then? "I settled it because it would have dragged on and on and been disruptive for me and a lot of people who would have been brought in for depositions." His expanding team of political advisers fervently hope the story will be old news by the time Bloomberg is expected to announce in June. "If it had to come out," one of them says, "it's much better to do it now rather than a week before the election."