In 1966, some 30 years after the publication of her previous novel Good Morning, Midnight, Jean Rhys achieved huge success with Wide Sargasso Sea, the tale of the white Creole heiress Antoinette Cosway: her Caribbean childhood, unhappy marriage and relocation to England where, imprisoned at Thornfield Hall, she becomes the "madwoman in the attic" Bertha Mason, the first Mrs Rochester in Charlotte Brontë's Jane Eyre.
Wide Sargasso Sea is now a classic in its own right and a fixture on reading lists for postcolonial literature degrees. But it is, first and foremost, a prequel, albeit one written without any kind of commercial premeditation. Its release wasn't marked by publicity screaming: "Jane Eyre - the saga continues!" Rather, its connection to Jane Eyre is intellectual and so, in a funny sort of way, incidental. Rhys wasn't trying to extend the Brontë brand, and if she'd tried to frame her intentions in those terms, nobody would have understood what she was on about.
Fast-forward 40 years and the story is very different. Sequels and prequels to classic novels or novel sequences are everywhere. This year alone there have been sequels to JD Salinger's The Catcher in the Rye, Bram Stoker's Dracula and Douglas Adams's Hitchhiker's Guide to the Galaxy series, and a prequel to Dashiell Hammett's The Maltese Falcon, among others. One of 2008's biggest-selling books was Sebastian Faulks's attempt at a new Bond novel, Devil May Care. (Perhaps surprisingly, Faulks has said he won't be writing another: "My contract did offer me a second go, but definitely not. 'Once funny, twice silly, three times a slap', as the nanny saying goes.")
"Success invites repetition aimed at finding and maintaining special formulas to recreate the triumphs of the past," the academic Edward H Friedman declared in a recent paper, Insincere Flattery: Imitation and the Growth of the Novel. "Not surprisingly," he concluded, "the victories tend to be defined more in commercial than in aesthetic terms." Some would argue that Faulks's book was a commercial and aesthetic success: he was praised for his elegant and sympathetic recreation of Fleming's style. The veteran thriller writer Joe Gores's Maltese Falcon prequel, Spade and Archer, has been written in a similar spirit. Authorised by Hammett's estate, it's an ingenious, rigorous novel that takes us back to 1921 and the founding of the San Francisco private detective Sam Spade's agency. Gores mimics Hammett adeptly and includes plenty of the close physical descriptions of characters for which Hammett is famous, but his intentions always feel honourable: he isn't simply trying to dazzle us with clever-clever pastiche.
At the other end of the spectrum is Fredrik Colting, who earlier this year published a somewhat anaemic sequel to JD Salinger's The Catcher in the Rye under the pseudonym John David California. "I think this book can win a contest for the most poorly written 'sequel' ever," commented one Amazon reviewer. The reclusive (and notoriously litigious) Salinger evidently agreed. He sued Colting for copyright infringement, his lawyers arguing that the book was "a rip-off, pure and simple".
Once copyright has lapsed, however, a book's characters and plot are up for grabs. In 2001, François Cérésa wrote a sequel to Victor Hugo's Les Miserables. Hugo's family disliked the book and tried to ban it and to extract from Cérésa damages of ?685,000 (Dh3.7 million). (They were particularly cross with him for resurrecting a character who died in the original novel.) But the Paris high court ruled that Cérésa had done nothing wrong as the novel and its characters were in the public domain. Similarly, Dracula has been out of copyright since the 1930s. The latest sequel to it, Dracula the Un-Dead, is the work of Stoker's great-great-nephew Dacre and the screenwriter Ian Holt. Dacre Stoker had never written a novel before: Holt made the initial approach to the former private school headmaster and was upfront about "needing a Stoker in the project" to give it authenticity.
In truth, opportunistic sequels have been with us as long as novels themselves and have often taken the form of parody: Henry Fielding's Shamela from 1741 is a satirical sequel to Samuel Richardson's Pamela, which had come out the year before. It was in the early 1990s, however, that publishers stopped being coy and began to promote them as quality reading experiences. Scarlett, Alexandra Ripley's 1992 sequel to Margaret Mitchell's only novel, Gone With the Wind, got a pasting from critics but spent 28 weeks on Publishers Weekly's bestseller list. In 2005, another American classic got the sequel treatment when Geraldine Brooks published March, the story of the father of Louisa May Alcott's Little Women, specifically his Civil War experiences.
One theory behind the current sequels boom is that, in times of economic crisis, readers want the consolation of the familiar. But Benedicte Page, associate editor of The Bookseller, thinks there's more to it than that. "In the case of books like the Bond one, it's very much to do with estates looking for ways to move properties on and make them attractive to new generations of readers," she says. "There's a lot of strategic thinking and a desire to create an event around a particular author. The fear is that an estate will stagnate if a creative way isn't found to revive it."
Publishers like sequels too, says the literary agent Ivan Mulcahy: "It may indeed be to do with the recessionary appeal of the familiar, but it's more to do with publishers being assured that a well-known book - as a brand - will win the kind of media attention that an equivalent marketing and publicity campaign for a new, unknown author couldn't hope to match." The Bond author Fleming's estate is controlled by Simon Trewin at United Agents. He's been responsible not just for Devil May Care but for other recent Bond spin-offs such as Charlie Higson's incredibly successful Young Bond series and the less successful (because poorly executed) Moneypenny Diaries. Many key estates are owned by companies that exist solely to control the exploitation of copyrights: Winnie the Pooh will shortly be having new adventures in the Hundred Acre Wood thanks to a new ruling by the firm that runs AA Milne's estate, the Pooh Properties Trust. One of the most successful copyright management companies is Chorion, which looks after the estates of Agatha Christie, Dennis Wheatley, Raymond Chandler and Georges Simenon and classic children's character "brands" such as Mr Men and Paddington Bear.
Chorion was behind the British TV company ITV's recent controversial Miss Marple reboot, which played fast and loose with Christie's plots and altered Jane Marple's character to give her a romantic backstory. Purists were outraged, but Chorion didn't sanction the changes just to wind them up: it would argue that part of what its website mission statement calls "careful conservatorship" is ensuring properties shape-shift to meet the narrative demands of new generations of potential fans. (The Beatles' record label, Apple, had Chorion's brand strategising in mind when it approved The Beatles Rock Band. Besides, copyright on The Beatles' first album is due to expire in 2013, so hay must be made while the sun still shines.)
Chorion has just licensed an addition to Enid Blyton's Secret Series written by a fan, Trevor Bolton, who had never been published before. It was sent to Chorion on spec by the Enid Blyton Society, around which Bolton, an active member, had circulated the manuscript. Which raises a key question: what distinguishes sequels from fan fiction - the kind of imaginings that clog up internet forums devoted to Star Trek and The Lord of the Rings?
Not necessarily all that much, admits the bestselling children's author Eoin Colfer, who has called And Another Thing..., his addition to the late Douglas Adams's Hitchhiker's series, "very authorised fan fiction", adding: "This is not part of the Douglas Adams oeuvre." (Colfer has also admitted, quite happily, that the book came about after his agent had lunch with the agent of Jane Belson, Adams's widow, who controls his estate.) And Another Thing... has been well received by most Hitchhiker's fans, perhaps because it doesn't try too hard to imitate Adams's distinctive voice.
The author served least well by writers of sequels and prequels is undoubtedly Jane Austen. As if Pemberley, Emma Tennant's notoriously awful 1992 sequel to Pride and Prejudice, wasn't enough, there's also Joan Aiken's Eliza's Daughter (a sequel to Sense and Sensibility), Janet Aylmer's Darcy's Story (self-explanatory) and, from as long ago as 1929, another Sense and Sensibility addendum, Edith Charlotte Brown's Margaret Dashwood, or Interference. Unfinished material is always a temptation and Austen left two incomplete manuscripts, The Watsons and Sanditon. They have inspired numerous attempts to finish them off, some by Austen's niece Anna Austen Lefroy.
Austen attracts sequel writers because she left us only six novels - not nearly enough to satisfy demand. The problem is, her witty but concise style is much harder to imitate than people think. Ironically, a book that manages it quite well, perhaps because of the way it intersperses pastiche material - in this case, "all-new scenes of bone-crunching zombie mayhem" - with chunks of Austen's original text, is the original mash-up novel, Seth Grahame-Smith's Pride and Prejudice and Zombies.
Would Austen approve? Probably. It is a truth universally acknowledged that she had a great sense of humour.