When I embarked upon my research for Paper Tigers, I made a list of the cast of characters and then pinned their newspaper empires on to a world map, which I constantly updated. My study at home became a war room, the battle lines shifting continually, as Conrad Black of the Telegraph invaded Jerusalem (by buying the Post) and Australia (the Fairfax papers) while Lord Rothermere, Rupert Murdoch and the late Robert Maxwell swept across Eastern Europe, snapping up the old communist broadsheets.
In America, this metropolis or that fell to the Chandlers (of the Los Angeles Times), the Sulzbergers (of the New York Times), or to one of the new generation number-crunchers such as Dean Singleton or Ralph Ingersoll, while shadowy newspaper tycoons in Hong Kong and India were forging vast empires about which I then knew almost nothing.
One afternoon I wrote to all 30 of them, requesting a first interview. Later I would want to visit them several times, but it seemed wise to begin modestly. Only six proprietors replied, five declining courteously ('I never give interviews, but good luck with your awesome-sounding project') and one saying yes (from Houston - 'I'd be honoured to be considered eligible').
There are two great challenges inherent in interviewing newspaper tycoons. First and foremost is that they congenitally dislike giving interviews.
All day long, their own newspapers interview politicians, celebrities and business magnates, and yet they are almost paranoiacally publicity-shy themselves. If there is an irony in that, then they appear not to recognise it.
Hunt through the archives and cuttings libraries and you find next-to-nothing about the personalities of the owners, aside from Murdoch and Maxwell.
Like First World War generals, they stay well away from the front line. One of the perks of proprietorship is that your own newspapers of course can't touch you, and rival owners discourage the publication of both praising profiles ('too helpful to the opposition') and negative ones (in case they are reciprocated).
The second problem is that they are never in one place. Write to them in New York, Toronto or wherever, and your letter is forwarded round and round the world, as it fails to catch up with the owner on his yacht or corporate jet.
I bought shares in all their companies - about pounds 20 worth in each - which guarantee the glossy report-and-accounts and entitled me in letters to include the emotive line 'As a shareholder in the Washington Post Company' etc. Then I began faxing them, couriering them messages, cajoling until, like a fisherman on the bank of a notoriously difficult river, I felt the first pull on the line.
SEVERAL proprietors, such as the Aga Khan, who owns a newspaper empire in East Africa, sent emissaries to scrutinise me. I had a lunch at the Garrick Club to talk about the kind of questions I might ask His Highness, should he allow me to see him.
I met Conrad Black in the Savoy Grill and the American publisher Ralph Ingersoll in the Ritz, both of whom insisted on sounding out my attitude themselves, which made me feel like a prospective Hindu bride.
Tony O'Reilly, the Heinz tycoon who controls much of the Irish and Australian press, had his people check out my previous journalism and books. I must have passed (Did I want to pass? What does that say about one?) because he rang me himself in hospital, just as my wife was giving birth to our first child, to suggest a rendezvous in Cork the next day.
Interviews, when they were eventually achieved, were invariably at short notice and across the world. I flew to Los Angeles to see Murdoch at 24 hours' notice, and to Hong Kong to see Sally Aw Sian, the eccentrically powerful Chinese tycoon, within a few hours of her go-ahead.
It took almost three years before the most defiantly elusive owners began to capitulate, and then there was almost a stampede of them changing their minds. The reason for this is, I believe, quite simple. They didn't want to be left out. In the early days, when I'd visited only seven or eight of them, they thought it smarter to decline to be included. But as the proportion changed - and they were always very insistent on knowing which of their peers I'd already seen - there came a moment when it seemed preferable to be in.
'Have you seen Murdoch yet for your book?' asked Robert Maxwell the first time I saw him.
'Not yet,' I replied.
'I shouldn't bother,' Maxwell advised me conspiratorially. 'His empire won't be around by the time your book is published. You must trust me on this.'
One of the most entertaining spectacles while writing Paper Tigers was watching the way that proprietors were always suggesting I exclude this rival or that ('I'm surprised you're including Lord Stevens (of the Daily Express) in your book' or 'Are you really convinced that Arthur Ochs Sulzberger Jnr (of the New York Times) merits his place?). Having eventually resolved to appear themselves, they set about suggesting to me that the club should stay exclusive.
Which were the most elusive? Rupert Murdoch certainly, because his schedule is impenetrable and changes so rapidly. Katharine Graham, of the Washington Post, because she never, ever talks about herself ('There's nothing in it for me'). She is the most famous woman in Washington, but statistically one has more prospect of walking on the moon than getting an audience with her.
Samir Jain, the natty marketing-led owner of the Times of India, who eventually changed his mind and then obliged me to sit in on one of his episodic four-hour board meetings at which he does all the talking. Rothermere because he hasn't given an interview for years, and I still don't know on what whim he did so this time.
One of very few missing players is Robert Hersant, owner of Le Figaro. After the war he was censured as a collaborator and banned from owning newspapers for five years, and since 1950 has never submitted to a single major interview.
I WAS determined to see Hersant in the flesh, and had been told that every weekday he left the Paris building at 12.35pm to be driven to lunch. A silver Mercedes would draw up at the front entrance, M. Hersant descend in the lift, cross the gleaming lobby and climb into the back seat of the car. I decided one morning to station myself across the avenue and spectate.
At 12.35pm the silver Mercedes arrived at the ramp leading down to the entrance. Two minutes later there was a flurry in the lobby, and the chauffeur walked round the car to open the passenger door. Just then two sinister security guards appeared alongside me on the pavement, intentionally blocking out my view across the street.
'You are searching for a taxi, non?' said one firmly grasping my arm. 'You will best find a taxi at the other end of the street.'
By the time they moved away, the silver Mercedes was turning the corner.
Nicholas Coleridge's book 'Paper Tigers' is published tomorrow by Heinemann ( pounds 17.99).