It is will, not greed, that makes you write a bestseller

Tony Parsons says that blockbusters are written by people who give their heart and soul to something they believe in utterly: if you try to write just for the money, you won't get it When Ernest Hemingway met Harold Robbins, the grand old man of American literature asked the alpha male of the bestseller list why he wrote. 'Wealth,' said Harold Robbins. 'And I got it.' Of all the lies that Harold Robbins told in his life — the fantasy most often repeated as fact is that his first wife was a Chinese dancer who died of a parrot bite — this was the most outrageous.

Harold Robbins — who liked to boast that he was the only author 'with his own goddamn yacht' — did not write for money. Nobody on the bestseller list writes for money. The people who write for money never make it to the bestseller list.

Harold Robbins's remains are in the Palm Springs Mortuary and Mausoleum, and they rest in an urn made in the form of one of his fat, feisty blockbusters. That is not the act of a man with contempt for either his readers or his craft. Robbins wrote the best books he could, and he wrote them because he had to.

Robbins, although almost completely forgotten today, sold 750 million books and for decades was the bestselling novelist on the planet. He wrote a lot of trash, but he also wrote some cracking yarns. And let no one doubt that Robbins was as serious about The Carpetbaggers and The Adventurers as Hemingway was about The Sun Also Rises and A Farewell To Anns.

That is what people don't get about the bestseller list. Everyone on it is sincere. 'You should write one of those chick-lit books,' I have heard numerous idiot boyfriends tell their girlfriends over the years. 'You would make a mint.'

But Bridget Jones was not written that way. Bridget Jones came from somewhere deep inside Helen Fielding, and its genius was that it wrapped up the fears and aspirations of a generation of women — women worried about never becoming mothers, women worried that they were past their sell-by date, women worried about how many more inappropriate men they would have to sleep with before Mr Good Enough came along — and it struck a chord in women all over the world.

The books that Harold Robbins wrote for money are the books that nobody ever read. Anything that gets on to the bestseller list deserves to be there. And even if it is not your cup of Darjeeling, never doubt that the author of The Da Vinci Code is as serious in his intent as the author of Atonement.

Every bestseller is an act of will from somewhere real. A bestseller is organic. Often it is an idea — an incident, a hunch, a headline — that will just not let you go. In 1964 a journalist called Peter Benchley read about a fisherman called Frank Mundus catching a 4,550-pound great white shark off Long Island. But it was ten years before Benchley published Jaws.

Erich Segal knocked about Hollywood doing well-paid but anonymous work such as the screenplay for the Beatles cartoon Yellow Submarine. Segal had a screenplay about a Harvard frat boy falling in love with a Radcliffe brainbox. Nobody wanted to know. His agent told him to bang it out as a novel. Love Story sold 21 million copies and — naturally — got turned into a Hollywood movie.

For every novelist in the world, the money is always less than you might think or more than you could imagine. Dan Brown read Sidney Sheldon's The Doomsday Conspiracy while on holiday in Tahiti in 1994 and was convinced he could do better, yet his first three novels had print runs of fewer than 10,000 copies. Assuming those books took about 12 months to write, that means that for a very long time Dan Brown's fiction earned him less than the minimum wage. But when he wrote The Da Vinci Code and sold 60 million copies, the flop backlist was pulled out of the remainder rack and quickly annexed to the bestseller list. Last year Brown's income was estimated at $76.5 million An act of will from somewhere real — even if you need the money, even if you are desperate for the loot, even if you are on your uppers — still has to be done with fire in your belly and an idea that wakes you in the middle of the night. John Grisham, the embodiment of the airport novelist, took three years to write his first book, A Time To Kill, after witnessing the harrowing testimony of a 12-year-old rape victim. Grisham's legal thrillers make him over £10 million per annum, but it began with that little girl in the De Soto County Courthouse in Mississippi, and for Grisham it had absolutely nothing to do with light entertainment.

They say write about what you know but that's not quite it. J.K. Bowling has no particular interest in the occult. 'I believe in God, not magic,' she says. Yet Harry Potter has made Rowling £7 billion, and introduced a generation of children to the joys of the printed word.

The first Harry Potter book was famously written by hand in an Edinburgh café when Rowling had walked around for long enough to get her baby daughter to nod off. Those were hard times. Rowling was not long divorced, she had just seen her mother die and she was an unemployed single parent living on benefits. How do you find the time and energy to write a book with all that stacked against you? Because Harry Potter fed some profound need in Rowling's soul, perhaps a need for — what? Escape? Transcendence? Innocence? Old certainties? Do not write about what you know — write about the things that will not let you go.

It's not that the unknown writer doesn't need the money — they always need the money. But it has to be about more than that; it has to be an act of will from somewhere real, or I guarantee you will fail.

In the 1960s an Italian–American journalist with mounting debts remembered a phrase used by Joe Valachi at the 1963 Congressional Hearing on Organized Crime — The Godfather. Mario Puzo wrote his novel and, like Love Story, it sold 21 million copies — which seems to be the sales figure you get when everyone who buys books buys your book. Puzo gave every impression of wanting to repeat that success but he was too cynical about it. None of his subsequent books — with names like Omerta and The Sicilian — came close to matching the success of The Godfather, because Puzo forgot the golden rule of the bestseller list. Never for money, always for love.

That doesn't mean you can't study the competition. Many a bestselling author starts out with a stack of the currently hot titles on his desk. Frederick Forsyth did it before he wrote The Day of The Jackal, possibly the greatest thriller of all time and yet a book which defies the fundamental rule of the genre — because you know how it ends. You know that no hit man assassinated General De Gaulle, but it did not matter. Forsyth studied the rulebook, and then he tore it up. Every bestselling author must do the same. If you spot a bandwagon, then it is already too late to clamber aboard. You need your own set of wheels. If your book does not grip you by the throat, then it will not do the same to anyone else. This is why so many bestsellers are a kind of secret life story that incorporates fears, hopes and all the darkest places, a dream world more potent than the real world could ever be.

James Bond shared much with his creator — both gamblers, both snobs, both fussy as old maids about food and drink. Bond and Ian Fleming smoked the same number of cigarettes a day, they wore the same clothes, they both had a bachelorhood that extended into middle age and a sweet tooth for the wives of other men. But Bond was a man of action in a way that the desk-bound Fleming never was, even during the war when as an intelligence officer he sent other men off on their missions. The heroic 007 of the books is far closer to Captain Valentine Fleming, the father killed in France in 1917. Despite all the similarities, John Pearson calls James Bond Fleming's 'dream-self. ... an uncomplicated character who compensated his creator for his own tortuous temperament'.

Ian Fleming graphically demonstrates what you have to do to get on the bestseller list. You just have to open up a vein.