Law firm must ponder going to bat without its heaviest hitter.

AT 76, Bert Fields is no spring chicken.

But as one of Los Angeles' best-known celebrity lawyers, his practice is alive and kicking. Not only does he represent some of Hollywood's most well-known actors--Tom Cruise, Warren Beatty, John Travolta and many others --he's a legal thorn in the side of Walt Disney Co., practically the only studio he doesn't represent.

So when Fields acknowledged two years ago that he had been contacted by federal investigators as part of a probe into illegal wiretapping, the entertainment world took notice. So did his law firm, Greenberg Glusker Fields Claman Machtinger & Kinsella LLP, whose financial success has been built largely around Fields' client base.

Though no indictments have been brought, the investigation is raising an uncomfortable question around the firm: What happens when Fields is gone?

"There's this concept that we are Bert Fields," said Norman Levine, managing partner of Greenberg Glusker. "Obviously, if Bert were to retire, those clients would have many choices. But we believe that they are well-connected with our other lawyers and that a lot will stay."

It's a gamble for the 46-year-old law firm--and not only as it relates to Fields. In recent years, members of the firm's five-person management committee, recognizing that most of its senior partners have reached their 70s and 80s, have tried to bring in fresh faces, shift client work to younger partners and reduce an overall reliance on Fields' book of business. But with 20 percent of overall revenue still coming from Fields, the transition has been slow.

Fields, who denies any involvement in illegal wiretapping, admitted that his Rolodex means a lot to the future of his firm. "Obviously, I make a substantial contribution," Fields said. "But I take out a substantial amount, too."

Entertainment niche

Greenberg Glusker was founded as a business law firm in 1959 by Arthur Greenberg, Philip Glusker and Irving Hill, a former U.S. District Court judge who has since died.

In the 1980s, Greenberg, a business litigation lawyer, served as managing partner of the firm. Now 78, he is still a partner but no longer gets involved in management issues. Glusker, now 81, has retired. Among other partners, Stephen Claman, a 73-year-old old real estate and corporate attorney, has stepped out of management, and Sidney Machtinger, who handled estate planning, has retired.

The firm's entertainment niche developed under Fields. He represented former Disney executive Jeffrey Katzenberg in winning a $250 million settlement following a dispute with then-Chairman Michael Eisner. He also handled negotiations for Bob and Harvey Weinstein, former co-chairmen of Miramax Film Corp., in their contract dispute with Disney. In the past few years, he took on Disney again with a royalty suit over alleged rights to "Winnie the Pooh."

It was his 1993 representation of pop star Michael Jackson, who had been accused of molesting a young boy, which tied him to Anthony Pellicano, a private investigator and a prime suspect in the current federal investigation. Pellicano, long known as the sleuth of the stars, is in jail after pleading guilty to possessing plastic explosives and hand grenades.

As part of the probe, investigators have interviewed several celebrities and other lawyers who have hired Pellicano over the years to determine if they were aware of the illegal wiretaps.

"I've been told that I am a subject, not a target, of the investigation," Fields said in 2003. "But I have never in any case had anything to do with illegal wiretapping. I don't do that."

Fields declined to comment further on the case.

Levine would not say how much Fields makes for the firm. But former lawyers and competitors estimate he brings in about 20 percent of the $60 million in revenue. Fields, who shuns any involvement in management, declined to say anything about the value of his business.

"Bert Fields has always been in a class by himself," said Michael Grace, a partner at Grace & Grace who earlier headed the intellectual property department at Greenberg Glusker. "He isn't the kind of guy who would hang out at the water cooler. He's got a very active practice."

While he has no plans to retire, Fields said he has been grooming several of the firm's lawyers to take over when he's gone. In many cases, he works with a younger partner, an associate and a paralegal while he takes the major depositions and argues the most important motions. He turns over lesser cases to younger lawyers.

But in many high-stakes cases, clients may be less willing to pay for anyone other than Fields. "Obviously, some are going to say, 'Bert's the guy I was with and now I want to go with X,'" Fields said of his clients. "But I think the firm is well-situated to carry on just fine."

Comings, goings

Greenberg Glusker, whose advertising slogan is "the counsel you keep," has been preparing for Fields' departure since 1999, Levine said. One of the biggest moves was to lure Dale Kinsella, now a name partner whose clients include Mike Tyson, Sean Connery, Sean Penn and James Woods. Kinsella and 11 other lawyers at his former firm, Kinsella Boesch Fujikawa & Towle LLP, joined Greenberg Glusker in 2000.

More recently, the firm brought on celebrity lawyer Howard Weitzman, whose clients include Sugar Ray Leonard and director Ivan Reitman, and David Stanley, most recently executive producer of Telepictures Productions Inc., who will work in the firm's entertainment transactional practice.

Levine said the six name partners, including Fields, account for less than a one-third of the firm's business. Entertainment clients not tied to Fields' business include Univision Communications Inc., Mattel Inc. and composer Hans Zimmer. He also said the firm intends to emphasize two other practice areas: real estate and estate planning.

"If Bert Fields left 10 to 15 years ago, it would have been a devastating economic loss because he had accounted for a large part of the firm's practice," Levine said. "But over the last 10 years, our goal is to make sure other people have their own independent practice."

Still, there have been high-level departures. Among them was James Hornstein, a litigator and member of the firm's management committee who represented Twentieth Century Fox Film Corp. Another former member of the firm's management committee, Michael Bales, left to set up his own firm in Beverly Hills. Neither returned calls.

Ann Kane Smith, former chairwoman of the labor and employment practice group, left in January 2004 to become a partner at Thelen Reid & Priest LLP. Smith did not return calls.

Three months later, Miriam Beezy, who built the firm's existing intellectual property practice for three years, left to head the trademark and copyright practice at Foley & Lardnet, while Dale Goldsmith, a top real estate lawyer who represents the Los Angeles Dodgers and United Airlines, left to form a new firm, Armbruster & Goldsmith. Beezy and Goldsmith declined to comment.

The inquiry involving Fields is not believed to be a factor in any of these departures. Instead, they faced difficulties trying to develop their own business at a partnership dominated by Fields, say several former lawyers of the firm.

Meantime, Fields, who notes that his parents lived to be in their 90s, said he does not intend to go anywhere soon. "Maybe I'll be a doddering old fool and they'll ask me politely to go," he said.