Mayor Giuliani's friends and advisers typically list among their possessions a law degree, a closet full of muted neckties and the gray pallor of an overworked bureaucrat, Then there's Elliot Cuker, the mayor's bow tie-wearing confidant and speech guru who's best known for persuading Giuliani to dress up as Marilyn Monroe at a charity event two years ago.

"A brilliant performance - people are still complimenting him," said Cuker, 55, a car dealer when he isn't palling around with the mayor. Even as he holds a minor City Hall title — chairman of the Mayor's Film and Theater Advisory Board — Cuker is a ubiquitous presence in Giuliani's orbit. Golf outings. Yankee games. Drinks at Cuker's midtown cigar bar. When Giuliani prepares an important speech, Cuker advises him on presentation.

If some aides have cast Cuker as a mere cheerleader, others insist he's a key player in their campaign to smooth the mayor's famously rough edges, a campaign that will grow more vital if Giuliani runs for Senate against First Lady Hillary Rodham Clinton. Referring to the public's perception of Giuliani as a combative mayor, Cuker said, "They miss the heart of the man, and not because it's their fault." The mayor, he said, "hasn't done much" to alter that perception. "The difference between us is that I think the toughest guy in the world, is usually the man who comes off the softest," Cuker said. "The greatest strength one has is functioning from a position of openness, not anger."

Mayoral advisers credit Cuker with encouraging Giuliani to lose weight and take up a hobby (golf). The mayor's more relaxed public speaking style, they say, is the result of Cuker teaching him to work without notes. "Elliot has a relationship with the mayor where he's able to touch the essence of his soul more than anyone in the inner circle," said Adam Goodman, who produced Giuliani's 1997 campaign ads. Said a senior adviser: "Elliot makes Rudy loosey-goosey. He has become his alter ego." For Cuker, the relationship's less obvious rewards include a highly coveted City Hall parking spot and a heads-up from the Department of Consumer Affairs that a reporter has asked whether any complaints were filed against his car dealership. "I know everything," Cuker said, chuckling. Giuliani did not respond to a request for an interview about the friendship, which began two decades ago when they met and learned they shared an interest in classic cars. (Giuliani once bought a Porsche from Cuker.)

In the late '70s, Giuliani, then in private practice, represented Cuker during an IRS audit that ended with Cuker paying back taxes and interest Cuker characterized the investigation as civil, not criminal.

By then, Cuker had settled into yet another phase of a life that began in Russia, where he was born in 1942 to parents on the run from the Nazis. They settled in Brookline, Mass., in 1953, where Cuker's father was a butcher and slum landlord. In the 1960s, Cuker moved to New York to pursue an acting career that has landed him theater and small film roles. His experiences have left him prone to a host of grand statements and outright fabrications. "By the time I was 6, I knew five languages," he said. He also is capable of overstatement. His resume claims he was the first white actor "invited" to join the Negro Ensemble Company, which the ensemble's founder disputes. "He wasn't the first," said Douglas Turner Ward. "There were a number of white actors who acted when we needed them, and there is no record of him ever working here."

Cuker said he drifted into the classic car business because he grew tired of being rejected for acting roles. His complex odyssey is only one reason that he and Giuliani are an unlikely pairing. If the mayor seems to eschew any form of public introspection, Cuker talks openly about his 25 years in psychotherapy. If the mayor seems buttoned-down, Cuker is as outlandish as his business card, which features a photo of him with a cigar jammed between his teeth.

His visage also can be found in a large painting that hangs on his office wall, a $10,000 portrait he commissioned of himself standing by a Rolls Royce.

A photograph of one of his ex-wives staring at him adoringly hangs beneath a spotlight in his bar. He married Noeline Hession, 25, in 1997 after dating her sister for several years. "It symbolizes every man's dream," Cuker said of the photo.

His political affiliation? Cuker says he's a Republican, then admits he's not a registered voter. "I don't want to get into it," he said, refusing to elaborate. He's more forthcoming about Giuliani's prospects against Clinton. "He's a much more substantial human being than she is," he said. As for the mayor's ultimate ambitions, Cuker said the inner circle has no doubt where Giuliani should end up. '"He'd be a wonderful President," Cuker said. "It's the perfect marriage, that position and what he's about."