The making of a bestseller

What makes a bestseller? Why is it that some books jump to the top of the bestseller lists and then stay for many months? The most obvious answer to this question is the author's name, and indeed most of the slots on the fiction bestseller lists are filled by the 'bankers', well-known authors whose books publishers can rely on to become bestsellers. Most people choose their fiction by author, so a new John Grisham, Danielle Steel, Josephine Cox or Donna Tartt seems like a sure thing.

But every so often the pundits are taken by surprise by a book that seems to come out of nowhere, leap into the bestseller lists and then just keep on selling. Partly this is the nature of bestsellerdom, which means that a bestselling book can draw a mass readership. But the enormous power of word-of- mouth and a strong, original theme should not be underestimated. Word-of-mouth was what sold Captain Corelli's Mandolin and made the author's career, after a number of well-reviewed but small-selling novels. Word-of-mouth, combined with bestsellerdom, was what made Alice Sebold's The Lovely Bones sell half a million copies in the UK by November 2003 and over 6 million in the States.

In the case of The Lovely Bones another factor seems to be at work. For the book is about a murdered girl who watches over her family from heaven. Opinions were divided - some found it mawkish, others strangely compulsive. Perhaps the reason why Cecelia Ahern's first novel, PS, I Love You looks bound for the top of the bestseller lists in spite of a critical slating is not just because she's the daughter the Irish prime minister. Perhaps it's also because it consists of letters from beyond the grave? This is 'popular fiction about death', which after the response to the death of Princess Diana and the tragedy of 9/11 people seem to want to deal with in fictional terms.

And what of Elisabeth Noble's first novel, The Reading Group, which has just shot to the top of the UK original fiction bestseller list? Well, the clever title says it all. A book about a reading group is bound to appeal to the many avid readers who are joining these groups.

So, a strong, original theme is a good starting-point, but it needs to be easy to convey, preferably through a good title, and deal with a topical theme .