To be continued: literary legends extended

As Andrew Motion announces he's writing a sequel to Treasure Island, we look at other sequels by established, popular writers.

Bobby Driscoll, left, and Robert Newton in the 1950 film adaptation of Treasure Island. Rex Features

When Jim Hawkins, the child hero of Robert Louis Stevenson's swashbuckling book Treasure Island, finally returns to Bristol with his "ample share" of the loot, he says behind clenched teeth: "Oxen and wain-ropes would not bring me back to that accursed island." No, but a former poet laureate with time on his hands might. For Andrew Motion has announced that he's writing a sequel to one of the all-time classic adventure stories.

In Return to Treasure Island, to be published by Jonathan Cape in 2012, Jim lives with his son just outside London. One day, Jim Jr is visited by a girl who, it's revealed, is Long John Silver's daughter. Naturally, she convinces him to steal his father's map - with its famous "x" marking the spot - and they hit upon a plan to run away and gobble up the rest of the treasure. Motion's sequel isn't quite a children's book - "there's quite a lot of dark stuff", he said last week - but then, with its mutinies and violence, neither was the original. Neither is this just literary opportunism on the part of Motion: Robert Louis Stevenson did leave the ending remarkably open. Long John Silver might be the baddie, but he somehow survives with enough loot to "live in comfort", and Hawkins leaves pirates marooned on the strange island.

So Return to Treasure Island is reasonably persuasive as a literary endeavour. But the Jonathan Cape publisher Dan Franklin - who said this was an exciting work of "literary ventriloquism" that would provoke "cries of delight" for fans of the original - will also have been eyeing the many, many pieces of eight that Motion's book could bring his company. And he would have done so because such sequels by established, popular writers are not just becoming more prevalent, they're doing incredible business for the publishers. When Sebastian Faulks wrote the new James Bond book in 2008, Devil May Care, it became Penguin's fastest-selling hardback ever. Somewhat strangely credited as "Sebastian Faulks writing as Ian Fleming", you do wonder how seriously the bestselling author of Birdsong and Charlotte Grey took the commission. He admitted he wrote Devil May Care in just six weeks and set it in the 1960s world of the original books rather than involving himself in any kind of complicated update.

Of course, Faulks wasn't the first author to extend the Fleming legacy. Surprisingly, there have been 32 new Bond books since Fleming's death; most have been unremarkable tales by unremarkable authors, but Kingsley Amis did add some gravitas with Colonel Son. Even then he didn't write it in his own name: it was credited to Robert Markham. And just as well because it was generally regarded as rubbish.

Fleming, though, is overshadowed by the bookcases of novels inspired by Arthur Conan Doyle and Jane Austen. There's even a name for the authors of such enterprises: continuists. Stephen King, Neil Gaiman and more recently the Pulitzer Prize-winner Michael Chabon have all had a go at Sherlock Holmes stories. There are scores of Pride and Prejudice sequels, mostly awful and seemingly cynical exercises, cashing in on readers' undying love for the source text.

To be a truly successful continuist is tough. It helps if you're already a well-regarded author of your own stories. But a respect bordering on an obsession for the originals is key. Eoin Colfer already had the highly regarded Artemis Fowl children's fantasy books behind him when he took on the challenge of writing the sixth book in the Hitchhiker's Guide to the Galaxy space drama, seven years after the death of its creator, Douglas Adams. He even spoke of his "semi-outrage" at the prospect of another author writing a sequel. But such reverence meant that And Another Thing... was a finely crafted addition to the series.

So close was it to Adams' style, it could have easily been passed off as a lost manuscript found in a vault. A relief not just to the fans but to the publisher Michael Joseph's balance sheet: more than 14 million people own a Hitchhiker's book. Similarly, last year, with the eventual approval of the AA Milne estate, Leo Benedictus wrote the first Winnie the Pooh adventure in eight decades. It was an absolutely gorgeous story, completely true to the originals and yet somehow given a knowing, modern twist.

So are these impersonations a bit of fun for the author, an easy payday for the publishers or a tug on the heartstrings for the nostalgic reader? In truth, they're a bit of all three. And if Motion gets his Robert Louis Stevenson homage right, he'll uncover his very own horde of literary treasure: a best-selling book.