It hardly seems a moment ago that Mr Murdoch, then an obscure but energetic small-time Australian newspaper boss of 37, made his mark in Britain, buying the News of the World. At 38 he snapped up the Daily Herald for pounds 800,000 and transformed it into the Sun. At 47 he took control of the Times and Sunday Times. He was 52 when he made his move into Hollywood, buying 20th Century Fox, and 57 when he sowed the seeds of a TV revolution, launching his Sky satellite service.
But on 11 March he has to face the awkward fact that he is 65 - an age when most businessmen retire, or at least take a back seat as non-executive chairman or president. Many notable business leaders have gone beyond 65. Lord Hanson was 74 last month. Lord Weinstock of GEC is 71. But the large institutional shareholders start to get nervous about companies run by elderly, entrenched, dominant patriarchs, especially if there is no obvious heir apparent being groomed to take over. And corporate history is littered with great business leaders in their 40s and 50s who somehow lost their touch in their 60s and 70s.
As far as we know, Murdoch has no intention of retiring. "He will die with his boots on," says one former Murdoch executive. He has never been busier. Last week, for instance, he was both negotiating the final details of a deal to beam his Asian satellite venture Star TV into China, and talking to John Malone's Tele-Communications Inc about pooling their US satellite interests. The workaholic Murdoch, busy shaping the first truly global media empire, barely has time to glance up as time's winged chariot hurries by. News Corporation shareholders certainly have no desire to see him go quite yet. The shares have rocketed by 600 per cent since 1990, when the empire nearly went bust, crippled with debts. Murdoch, more than any other entrepreneur, is the company. It is his preparedness to take risks with the company, to bet the farm, that has catapulted it into the media big time.
But the brutal truth is that no-one goes on forever. Murdoch's father, Sir Keith Murdoch, died at 67. His son looks fit and trim. He doesn't smoke and drinks only moderately. He skis, swims and sails. When in New York he likes to walk between appointments. But the lines are etched deep into his face and neck. According to one News Corp insider: "I think he does grow more tired than he used to - how could he not?" At some point, a successor has to be chosen and groomed if News Corp is to survive its ambitious creator.
Murdoch has made no secret of his ambition to keep the business in the family. No one doubts that a family member has a good chance of inheriting the top job. Over the years the family stake has been diluted from 46 per cent to 32 per cent - an inheritance worth more than pounds 1.5bn - but it is thought that Murdoch has recently been building up the family shareholding again. "He certainly has been making noises about doing this," says the insider, "and I think there is a considerable amount of effort being made."
News Corp has a nominations committee, a sub-group of the board which makes senior appointments. But according to the annual report there are only two board members on it - Murdoch himself and the company lawyer, Arthur Siskind.
The obvious eventual heir is Lachlan Murdoch, the elder of Rupert's two sons. Though only 24, Lachlan has undergone a breathtaking baptism of fire and carved out a name for himself in News Corp's Australian newspaper operations. He is intelligent, hardworking and has inherited his father's charm (see box below). He has also been appointed to a newly created executive committee, consisting of heads of News Corp companies, which lies immediately beneath the board. He is far away from the hub of News Corp in the United States, but one former Murdoch executive says: "Rupert regards the business as a family dynasty and I think he would have Lachlan as his first choice of successor."
If Lachlan ever believed it would be an uncontested succession, that hope evaporated last week when his sister Elisabeth, three years his senior, was appointed to a key position at BSkyB, the successful satellite venture 40 per cent controlled by News Corp. By shelving plans for an MBA to take the London job, Elisabeth has made it plain that she regards herself as a serious contender to wear her father's crown.
Last year she told the Sydney Morning Herald that she or one of her brothers would eventually succeed their father as chief executive. "One person will become CEO and the board will decide who that is. The way we see it, we are doing a service to ourselves and the company by all being best prepared to be that person. It's a huge company and I think no matter who is at the top, the others will not likely be many steps behind."
There are two other children - Prudence, a daughter now in her 30s from Rupert's first marriage to Patricia Booker, and Jamie, the youngest at 23, an ear-ring-wearing Harvard drop-out who runs a small record company producing hip-hop music in New York. Said to be the most entrepreneurial of the children, he shows no sign of joining News Corp, though he has admitted: "I guess I will always be involved - it is the family business."
In one sense, despite its pounds 6bn of annual revenues and sprawling geographical spread, News Corp is still a family business. Wherever he is, Murdoch has always taken calls from his executives at any time of the day or night. The children have grown up to the background noise of deals being done and executives being chided or praised.
But for the moment neither Elisabeth nor Lachlan would be old enough to take up the reins should Rupert fall under a bus tomorrow. According to the company insider: "They are very able, but how could any of them possibly fill Rupert's shoes? If he can last for another 20 years they might be fine. You couldn't expect them to run this kind of company with so little experience."
News Corp's revenues and profits are much healthier than in 1990, when the group came within a whisker of receivership, but it is still under pressure on several fronts, including Star TV and the Australian newspaper operations. "Banks still have a huge exposure to News Corporation," says Peter Cox, a prominent Sydney media analyst. "It's very much an empire that Rupert Murdoch has created, and the banks and other shareholders would be nervous about allowing it to pass into the hands of ones as young as Lachlan and Elisabeth.
"Lachlan may be a personable young man, but he has yet to do anything major in his own right. If something happened to Rupert, I believe that MCI, the American telephone giant and second biggest shareholder after the Murdoch family, would insist on stepping in."
Who could fill the gap between the departure of Rupert and the maturing of his children? For a while Andrew Knight, the former Economist editor and Daily Telegraph chief executive, looked the favourite. Murdoch hinted as much in 1990 after Knight was appointed chief executive of News International, the group's UK newspapers division. But Knight quit News International in 1994 and is now a non-executive director only.
Another possible stopgap is Hamish Maxwell, a former chief executive of the cigarette group Philip Morris, who is on the board. This looks a long shot - Maxwell is five years older than Murdoch. Aside from him, the board is utterly ineffectual, an insider says. "It is a bit of a dodo, totally in Rupert's hands."
So it seems existing managers will have to hold the reins until a son, or daughter, is ready to take over. Peter Cox says Murdoch still needs to rely for a long time yet on the services of his two right-hand men, Ken Cowley, chief executive of News Ltd in Australia, and Sam Chisholm, the Australian who heads BSkyB. Yet both men are approaching retirement and cannot be guaranteed to stay on the scene.
"This puts extra pressure on News Corporation," says Cox. "What Rupert needs is for Cowley and Chisholm to be there for at least another 10 years to cover the children's emergence and give stability to the shareholders. I don't think that's going to happen, so that could be a source of upheaval."
There is another possibility, which would keep News Corp in the family - Murdoch's formidable wife, Anna. According to another former executive who knows the family well, she could play a key role: "If Rupert goes on for another five years or more, then the chief executive job will go to one of his children, probably Elisabeth. But if he falls under a bus tomorrow, the chief executive would be Anna, his wife." There is a successful Australian precedent: when Robert Holmes a Court died, his wife Janet took over his empire and has been running it ever since.
Defenders of Rupert Murdoch will always tell you what a political moderate he is and how his conservative image is all wrong. Ask about novelist Anna, and they pause. Then they admit it: yes, her views are several leagues to the right of Pat Buchanan's. A fierce Catholic, she believes that abortion is a sin that should be illegal and is opposed to any form of birth control.
Rupert's second wife and the mother of his three younger children, Anna is no stay-at-home boss's wife. Tall and imposing with hard-set blonde hair, she is on the board of News Corp and clearly available to replace him as the company figurehead. She also keeps a close, even matronly eye, on the welfare of Rupert and his executives. She encourages Rupert to take naps during the day and brings in lunches of carrots and apples.
"She is very much part of the Mom and Pop store image that Rupert likes to instil in the company," says one insider. At Christmas, she is the one who remembers to send Christmas cards to her husband's most senior lieutenants and writes each one by hand. But she is also a hard-nosed operator that few in News Corp would dare to cross.
Rupert's and Anna's loyalty to one another is well chronicled. When Stephen Chao, a fast- rising executive at Fox, sneaked a male stripper into a Murdoch seminar three years ago, Rupert was so offended that he fired him - Anna was at the seminar. Anna, by turn, is known to react badly when press articles are unkind about her husband. "She feels that he is unfairly beaten up in the press," says Ken Auletta, a writer with the New Yorker magazine and long-time student of the Murdoch empire.
Of Anna's books, the most intriguing is Family Business. It chronicles what happens to a media dynasty when the father unexpectedly dies and - guess what - leaves no anointed successor. The torch is passed to a daughter who builds it into a global power. But when her own children begin to squabble over the fortunes of the empire, she sells out.
Clogs to clogs in three generations, goes the saw. The first generation creates the business. The second consolidates it. The third squanders it. Some family businesses have bucked the trend - David Sainsbury is the fourth generation in the family grocery business. Peter Baring was the sixth generation before Nick Leeson put an end to the family tradition.
There is no suggestion that Murdoch's offspring are idle playboys. People who know the family well say they are bright, serious, very hardworking and blessed with their father's charm. Even so, it seems doubtful they have the extraordinary risk-taking skills and vision of their father.
Former Murdoch executives are divided as to what would happen to News Corp after Murdoch's death. According to one: "It will be split up. It's Rupert's creation. It goes when he goes." He points out that with Elisabeth's experience in television and Lachlan's in newspapers, it might be possible to break up the empire and place the children in different parts of it.
Another figure who knows the company intimately suggests the group would survive and the share price might even strengthen without Rupert at the helm. News Corp would become less of a risk-taking enterprise.
What is certain is that the character of the company would change dramatically. John Malone, head of TeleCommunications Inc, is a friend of Murdoch. In 1994 he told the Wall Street Journal: "You won't find another Rupert Murdoch - he just doesn't exist."
How brother and sister measure up Elisabeth Murdoch
Age and status: 27, married to Elkin Pianim, a former investment banker, with one daughter, Cornelia.
Education: Brearley School on New York's Upper East Side, then Vassar College, New York state.
Experience: TV researcher on Australian documentary A Current Affair. Programme director for Fox Television. Television station entrepreneur.
Strengths: Good marketing and promotion skills. Prepared to be ruthless. Out of her 75 TV staff, 18 were sacked. Good eye for a deal. She bought her TV stations for $35m, increased profits and sold them a year later for a $12m profit.
Weaknesses: Sabre-rattling management manner. Now regrets issuing what came to be known as the Three Strikes Memo, threatening firings if any newscast contained more than three production errors.
Sound bite: "I think he [her father] plans on doing this until the day he drops... I just look forward to the day my brothers and I are ready to be his deputies, to help him. I'd like to be able to take a bit of the weight off his shoulders."
Age and status: 24, engaged to Kate Harbin, a McKinsey & Co consultant.
Education: Trinity School, New York. Princeton University, New Jersey. Degree in philosophy.
Experience: Farm hand in outback New South Wales. General manager of Queensland Newspapers. Deputy chairman of Star TV, publisher of The Australian. Recently appointed deputy chief executive of News Ltd.
Strengths: A zest for business, works long hours, approachable manner. "He has very much his father's brain," one journalist said. "All he talked about was figures." According to his grandma, Dame Elisabeth Murdoch: "Lachlan is idealistic, thoughtful and has strong self-discipline."
Weaknesses: "Not as tough as Elisabeth," according to one former Murdoch executive. Suffered setback last week after Australian court stymied his plan for a rugby superleague.
Sound bite: "I think that because of my father, or my relationship with him, the thing I have to do is to be extra cautious and to prove myself. I have to prove I'm serious."