Over the Fourth of July weekend at the billionaire Ronald O. Perelman's 57-acre East Hampton estate the Creeks, Vivi Nevo was in his element.
Mr. Nevo, with his fiancée, the megawatt Chinese actress Zhang Ziyi (the star of "Crouching Tiger, Hidden Dragon"), sitting on his lap, watched Jon Bon Jovi give an impromptu performance before taking a turn on the dance floor to Dave Mason's "Feelin' Alright."
A wind-up doll of kinetic energy, who bounds about like a shortstop, Mr. Nevo, who is 43, is said to be the largest individual shareholder of Time Warner, was once the largest private investor in Goldman Sachs, is engaged to China's most famous actress, vacations on Rupert Murdoch's sailboat, is the godfather of Lachlan Murdoch's son, counts Lenny Kravitz as a good friend and attended Madonna's wedding in 2000.
And many people, including even some of his close friends, a few of whom joined him at Mr. Perelman's estate over the Fourth of July -- and spoke about the party anonymously because it was a private event -- have no idea what his background is or how exactly he made his fortune.
Twenty years or so ago, Vivi Nevo, his first name a nickname for Aviv, was living in a studio apartment in the Concorde building on the Upper East Side of Manhattan. Today he is the media industry's Zelig, often referred to among his media friends as "the international man of mystery."
"He is everywhere, all the time, like no one I have ever seen," said Graydon Carter, the editor in chief of Vanity Fair, which frequently hosts Mr. Nevo at its high society parties.
Who is Mr. Nevo? An Israeli who took a modest inheritance from his family and parlayed it into a sizable fortune through savvy investing, much of it in media and Internet companies -- and into connections in the media world.