Warren Beatty loves him. Michael Jackson didn't listen. Madonna incurred his wrath. He'll fight anybody who says Tom Cruise is gay - and he's counselling Pooh. Interview by Ariel Leve

So why is Bert Fields crying?

It is a Saturday afternoon in Malibu. Fields is standing in his sunlit kitchen, sipping white wine and chopping tomatoes. He has paused because he is suddenly overcome with emotion.

'I'm sorry, it's still very painful,' he says. He is talking about his second wife, Lydia, who died in 1986 from lung cancer. They were married for 27 years. Her illness was one of the few battles he has lost. 'I had supreme arrogance. I've never been able to not solve a problem. I thought by reading everything I could get my hands on that I would find a way to beat it. But I couldn't do it.'

During her illness, his good friend Warren Beatty was terrific. 'He used to fly across the country to be with us at the hospital. He said, 'Don't underestimate the power of a movie star.' So there was this huge line of people and the doctor would usher us in - not having to wait on the line for four or five hours. It's a terrible thing, but I learnt a lesson about how unequal American medical treatment is. If you have clout, your treatment is superior.'He takes a sip of wine, resumes chopping, but his mood remains contemplative.

'It's hard when you live with someone for 27 years, happily, and then that person is suddenly gone.' He claps his hands together to signal that the anguish is over and refocuses on preparinghis super-sized salad.

After Lydia's death, he was single for five years. 'Twelve years ago, when we were both single, I hung out with Warren a lot.' His brown eyes twinkle. 'The fringe benefits were terrific. There was a girl I was with during the weekend and a different girl I was with during the week. I was constantly shifting between the two, and my house man, Hugo, would take the one girl's stuff out of the house when the weekend came and then move it all back in on Sunday night. They didn't know about the other.'

Then he met Barbara Guggenheim, the celebrated art consultant, when she hired him to represent her. She was being sued for $5m by Sylvester Stallone, who claimed she'd given him bad advice on an art purchase.

'Bert is like a venus flytrap,' Barbara declares. 'He sits in his office and waits for women to come in every 27 years. I met him on a Friday. He called me up and said we should meet for lunch the next day and discuss the case. I said no. He asked me out for Saturday night - I said no - and Sunday night, and I said no. Then he did something really bright. He said, 'If you go out with me for dinner on Monday night, I'll stay in New York.' I knew then. He was willing to put his personal life before work.'

Though Barbara never officially moved out to Los Angeles to live with him, she brought her things over on each trip, piece by piece, until she had moved in. After a while, she told Bert her friends were worried - she had gone out to California 'on spec' and they wanted to know what his intentions were.

'Bert said, "Tell them you're engaged," and I told him, "I can't lie!" So he said, "Okay, then. Let's get married." There was no hesitation.'

He told her right away about the weekend and the week girls, and asked for a little time to break it off. 'I can remember I flew out to LA for business and I called him and said, "Good news! I can stay the weekend." He said to me, "Oh, I haven't broken up with the weekend girl yet." What I liked was that he was totally open and straight about everything. With Bert, you always know where you stand. It's a luxury.'

Cooking is what Fields does to relax. At the end of the day he has a glass of wine and unwinds. Barbara reads aloud to him from history books while he cooks, which he always does because, he says, 'If Barbara cooked, we wouldn't eat.'

Since getting a legal letter from Bert Fields makes people tremble, the question that Barbara is asked the most is what it's like to live with him. 'It's very easy,' she says, 'providing you eat at 12.30 and eight.'

In Los Angeles, where people exfoliate marriages like flakes of dead skin, their union stands out. They have been married since 1991. Fields rolls up his sleeve to display his scars. 'These are from tennis,' he says, looking delighted. Every Saturday and Sunday morning, from eight until nine, he and Barbara play.

'Did he show you his scars from tennis?' she asks later. 'Tennis. No one gets scars from tennis.'

She describes her husband's competitive nature: 'One time we took a Spanish class together - they put you alone in a cubicle and you listen to tapes. On the tapes, the professor is teaching two people, and you give your answer along with the others. So I could hear Bert screaming out from his cubicle, 'Three to one! Three to one! I've got three, they've only got one!'

Lunch is served. Or rather, Fields presents his creation. They live in a simple and elegant beach-front home and he smiles when Barbara enters the room, and when he talks about her his words are weighted with reverence.

'I'm in love with my wife. Nothing is really unconditional in life except love for your children, but you can be in love and know that you can't imagine living without that person. That's how it is with Barbara. I like commitment. I want it. I like to have a buddy and I don't want more than one. Commitment for me, it's not an onerous thing. I've never been afraid of it.'

Barbara confirms they never argue. 'Never,' she says. 'I would lose, so what's the point?'In the morning while Fields is shaving they have 'legal hour'. Barbara asks him questions like: 'What happens if he says this? What do I say back?' She says she's been known to literally follow him out of the door and chase him down the path on his way to the car. 'He helps me enormously, even though it's probably not his favourite thing to do at 6.30 in the morning.'The more famous and powerful people are, the more there is to protect and control. And when people in this position want the best, they go to Bert Fields. His reputation isn't something he shies away from. This is the man who has almost never lost a case, who famously 'sacks' high-profile clients - Michael Jackson for not doing as he was told, Madonna for questioning a bill.

He and Barbara divide their time between Malibu and their other properties: a converted mill in the Loire valley in France, a house in an ancient fishing village in Mexico, an apartment in Manhattan overlooking Central Park and a Spanish-style 1920s house in the hills high above West Hollywood. Conspicuous consumption is an important part of Fields's life.

'It's only rational that if you buy a bottle of wine and it's $200, and you buy another bottle of wine that is $17, you assume that the $200 bottle is a much better wine. Similarly with lawyers - if a lawyer charges $850 an hour, you're naturally going to assume he's better than a lawyer who charges less - and often that's the case. I'm a great believer in the free market, and the market tends to determine these things.'

But in a land where lawyers are the butt of a million jokes, he stands out. Powerful people in Hollywood regard him as above reproach.

After lunch he sits on the patio, and it seems there is nowhere else he'd rather be. It is late afternoon, jazz emanates from the outside speakers and he talks about what he does in his spare time: writing. He has written two bestselling novels - The Sunset Bomber and The Lawyer's Tale - under the pseudonym D Kincaid. The hero, Harry Cain, is a slick Hollywood lawyer with a fiery sex life. After his then 92-year-old father read his latest 'sex-trash novel', he told Fields: 'This is fine, but when are you going to do something serious with your life?'

This provoked him to write and research his first nonfiction work, Royal Blood: Richard III and the Mystery of the Princes. He took people who had been vehemently contentious on each side of the controversy - did Richard kill his nephews in the Tower of London? Was he this hunchbacked, crippled guy Shakespeare wrote about? - and tried to bring a legal thought process to an examination of the evidence.

For the past seven years, when he's not at his day job, Fields has been working on a book about Shakespeare, using the same approach he used for Richard III. Who was he? Did he exist and was he the actual author of those revered works? So far, nobody has been able to find any manuscript or letter by Shakespeare, ever. There are six signatures by someone in Stratford-upon-Avon that may have been made by Shakespeare, but Fields finds them to be unreliable evidence.

He says there is no place better for research than the British Library or the Society of Antiquaries in London's Piccadilly or the College of Arms on Queen Victoria Street. He praises the British for their marvellous sense of history, and says doing research here has been very rewarding.

'I went to the College of Arms in London and said I would like to see the application by William Shakespeare to get a coat of arms and thus become a gentleman, and they brought me the original application. Put it right in my hands! I mean, these are priceless, priceless documents. I went to the British Museum library, and they were so helpful. You'd think the English would say, 'Why the hell do we need an American to do this kind of thing?' But they couldn't have been nicer.

'The great thing about the English is that they don't throw out anything. Old tax assessments from 1590 - stuff like that is all available.'

He says proudly that he is an Anglophile. He marvels at the civility of British courts. He likes the idea of wearing a wig and a gown too. 'Our system comes from the English system, and I'm very sympathetic to it. I've had a lot of cases in the high courts there, and I feel a great debt to them. They're the origin of our system.

It's the great English jurisdictional decisions that have made American law.'His maternal grandfather was British - a cockney who fought in the Boer war, came to America and did quite well. 'He was tough, a terrific guy - I really loved him. He was a bicycle-racer, travelled with the circus - an extraordinary guy.' Fields's grandmother was the elder daughter of a German family, a stutterer whom nobody wanted to marry because of her speech impediment. 'He loved her in spite of this. So here he is, this soldier, an Englishman, and even though he was a little crazy it was okay, because he wanted to marry her.'

Fields's grandfather was lucky. He went to Baltimore, Maryland, and near there found a swamp area where you could grow ferns. He grew ferns and sold them to florists all over the United States and became extremely wealthy and then, suddenly, lost it all in the Depression. His mother grew up a rich heiress from Baltimore and met his father, a surgeon, who married her when she was 16. They travelled around Europe for two years before they got the telegram telling them to come home immediately.

'All the money was gone. They were hugely wealthy and then, suddenly, totally wiped out. So they all got into an old Buick - not a Ford, because Ford hated Jews - and drove out to California and started a whole new life all over again.'

As he stands on his porch, his voice becomes fragile. 'I've often wondered, who really knows his father's heart? Who really knows what his father thinks about, his fears? None of us do. No son really knows what his father's thoughts are. My son, when my wife was dying, he was terrific, he was just marvellous. But I think, in general, sons don't know what their fathers are feeling. Fathers are very brave and bold. You don't tell your son, 'Son, I'm scared to death.' You just don't do that.'

He stops. For about 30 seconds there is silence. He is trying to get the words out but he is gripped by the depth of his feelings and surrenders to this profound sense of nostalgia.'When the war came, we were terrified.' He speaks slowly and, as he chokes back tears, his voice is barely audible. 'We were American Jews. If Hitler won we'd go to concentration camps. My father was probably 45. Didn't have to go in the army, he was a surgeon, but he gave up his practice to go into the service, because he felt he was a Jew who owed it to America. So in law school, yes, I felt I owed it to him. I said to myself, 'He's made this sacrifice to send me here and I have to do well.' So I did. It was to pay him back. I remember it with reverence, but it's not what motivates me now. Different things motivate me now.'the house, heading out for a walk down the beach, Fields points to a cluster of seaweed with delicate purple flowers at the base of his steps. 'See this? This is dying. It only lives for six months. Six beautiful months.'

Other than Barbara, he is pretty much alone. He doesn't tell a lot of people what he thinks and what he feels. He doesn't need to. But staring out at the sea, he reveals humility. 'There's something so primeval about the ocean. When you're near it, it makes you very conscious of what life is about. It makes you appreciate your place in life - which is not a major place. It really isn't.'

He talks about occupying a tiny place on the planet and sits down, burying his bare feet in the sand. The only sounds to be heard are from the seagulls and the waves. 'This goes on for ever. This will be here long after we are gone.'

His father urged him to pursue a career in medicine, but aptitude indicated that 'If I were to become a doctor, the medical profession would suffer greatly. Most of my patients wouldn't make it.' Instead he attended Harvard Law School. A former classmate recalls: 'Bert was this incredibly lively, good-looking and charming guy - but he was also an incredibly dedicated and serious lawyer who worked harder than anyone. He knew even then he wanted to be the best.'

After law school, Fields joined the air force during the Korean war and was stationed in England, where he was assigned courts martial - he dealt with two or three cases a day. His ambition since then has been to win, because it's all a big game. His secret is, he knows if he doesn't win, he'll be fine. 'You see it all over Hollywood - people who are blinded by ambition,' he says. 'I don't think of myself as ambitious - the things I have, they're not essential.'

Fields's son, James, from his first marriage to a college sweetheart, is a former lawyer. He says of his father: 'What differentiates him as a lawyer is that he has a remarkable creative spark. Great artists, inventors and mathematicians have it - insight. He will look at a problem in a totally different way, find arguments that no one would have ever thought to raise. He's beyond a technician. I know it sounds like I have hero worship - I don't. I know where he's strong and where he's weak.'

'People ask me all the time about Michael Eisner at Disney,' says Fields of his most famous adversary (and victim). 'He's an intelligent guy, works very hard, he's a difficult person, done things I wouldn't have done, but I don't feel vengeful at all, or judgmental.' In 1999, Fields represented Jeffrey Katzenberg - now of DreamWorks - the man credited with reviving Disney. He was suing Disney and Eisner for a breach of contract that Fields won - a reported $275m victory that resulted in a humiliating loss for Eisner and a double whammy against Disney, since Katzenberg used some of the payoff to set up DreamWorks with Steven Spielberg and muscle in on what was, until then, a monopoly of the animated movie industry. Even before that, Fields sued Disney on behalf of MGM to get back theme-park rights in Europe, claiming Disney hadn't lived up to its contract obligations, resulting in loss of profits. Fields won a unanimous jury verdict in that case.

He is renowned as the litigator who is able to argue any side of the case: suing a studio in one instance, representing a studio in another. Warren Beatty turned to Fields when Paramount told him that he had to cut four minutes from his movie Reds so that the film could be sold to ABC television. Beatty refused, and Fields argued that the director's right to the final cut is inviolate.

He won the case and established a legal precedent, then fought another case where he argued against it. He found himself supporting the opposite position when the director Michael Cimino's film The Sicilian ran over length and the studio ordered him to cut it. Cimino took out the action scenes. Fields, representing the studio, fought against the precedent that he'd established. Only this time around, he argued that Cimino's second cut was not a genuine final cut - that the first one he did he spent five months on, and the second cut he did overnight in anger. He won.

Fields argues serious legal issues that just happen to be on behalf of stars. His celebrity clients include Beatty, Tom Cruise and Dustin Hoffman, scores of top record companies and studios such as DreamWorks. He is working on a case that will go to trial in July on behalf of Sharon Stone, regarding payment she claims for the sequel to the film Basic Instinct. And other clients of the moment include the family that owns rights to Winnie-the-Pooh: Fields is once again suing Disney.

Because so many of his clients are famous, he is constantly fighting off extortion claims. He despises blackmail more than anything, and he protects his clients from this by swiftly going to the FBI or the district attorney, and by hiring a private investigator - whatever's necessary.

He advises clients never to pay off, and says he has never had a client who's been found guilty of the charges made against them.sun is beginning to set and, as we head back towards the house, Fields tells me that sometimes he and Barbara take the people they know and separate them into three categories. If they were all historically transposed to the days of the Holocaust, there are those that would hide them, those that wouldn't want to get involved, and those that would turn them in. He pauses, then says: 'Tom Cruise would be in the first category.'

Fields has paused at the edge of the surf. 'Do you know how many calls I get - daily - from people, all over the world - China! He's not gay.'

Asked why he thinks people care so much about Cruise's sexuality, Fields offers up this explanation: 'He is America's hero. He's gorgeous. I think every gay guy thinks, 'Boy, Tom Cruise, if he were gay that would be great.' And I understand that. He's a lovely guy, a delightful person. If I were gay, I'd like it if he were gay. Being Jewish, I wish he was Jewish. He's such a good guy. If I were Catholic, I would want him to be Catholic.

'It's become an urban legend that Tom is gay. And from time to time, people come along and they get some exciting publicity by saying, 'I had an affair with Tom Cruise!' But invariably it isn't true. Sometimes, if they have some money, we take some money from them for saying that, but whatever money we get Tom gives to charity - he doesn't sue for the money. He has a great sense of humour about it. And we've thought a lot about whether we want to do this or not, because he could just shrug it off.'

The reason they do this - litigate - is that when something is said today, it's in a computer for ever. Fields is fiercely protective of the truth. His strategy has worked. In spite of the years of rumours, nobody really cares whether Tom Cruise is gay or not; the main thing is that his box-office appeal hasn't been tarnished.

What wins Fields the fees he commands as well as the respect and friendships is the conviction among people with power that he is guided by principle, and that he wins. He fired Michael Jackson because when Jackson was accused by a 13-year-old boy of molesting him, Fields believed Jackson was innocent, believed he had evidence that would prove it, and that they would win in court. But Jackson ignored Fields's advice to fight and paid off his accusers. 'I don't think his career will ever go back to what it was,' Fields says. 'He's a brilliant artist and a very sweet guy - and now he will always be thought of as a child molester. It's too bad. But I just couldn't help him.'

There are other clients who have been given the sack, says Fields. 'I've fired Madonna and Donald Trump - I've fired lots of people. My friend John Goldsmith is now the head of Paramount, but in those days he was the head of Sony. And one day I fired Sony, and John called up and he said to me, 'Bert - who is your career counsellor? Icarus?'

'Madonna, when she was making Evita, was in trouble because she was associated with the Peronistas, and there were Argentine political parties that were violently opposed to her playing this role,' Fields says. 'Her manager called and asked me if I could help her. I really wanted to, and I called a client and friend who was a Latin American who had a lot of clout. So within 24 hours, the president of Argentina was standing on her balcony saying, 'Don't hate her.' As a favour to me, he saved her.

'I said to myself, 'Should I bill Madonna a premium?' I certainly made life much easier for her - and I might have saved her life. But I said, 'No, I'm not going to do that.' Instead I sent her a bill for $2,500 - which was the time I spent talking on the phone to this Latin American guy. So her manager calls me and says, 'Can you please give me a rundown of these charges? Madonna thinks they're outrageous.' I said, 'You know what? Don't pay me anything. Just never have her call me again in my life.'

Looking back on the event, he says: 'Maybe she didn't know - she didn't pay attention. It could have been her manager's fault.'

Just at that moment, a dolphin appears above the waves - and then dives straight back down. 'Ooh, look at that!' he squeals. 'Look! Look! Those are real dolphins.'

On the walk back to the house, Fields quotes a favoured line from Arthur Miller's play Death of a Salesman - a line that he clearly feels defines him. 'Willie Loman is talking to his friend Charlie, whose son has gone to law school. Willie Loman's son is a failed football player who never did well. Charlie's son is arguing a case the following week in front of the Supreme Court. So Willie says to Charlie, "That's amazing! Your son's going to argue a case before the Supreme Court and he never told me about it!" And Charlie says to him, "He didn't have to. He's doing it." Just like Bert Fields.