UK: The movie of The Da Vinci Code is due in May, but a lawsuit could spoil the party, writes Shane Hegarty.
Just when you thought it was safe to go back into the bookshop, The Da Vinci Code is back.
The movie, starring Tom Hanks, will be released in May. Five million new copies of the book are being printed. And in a twist that could prove as dramatic as anything Dan Brown came up with, on Monday the British High Court will hear a lawsuit that threatens to derail the whole enterprise.
Brown has sold 40 million copies of the novel in which a hero and heroine dash from Paris to Scotland solving clues that might uncover the Holy Grail and a Vatican conspiracy to protect the true history of Jesus.
It became the quickest-selling adult novel of all time.
But the authors of a non-fiction book, The Holy Blood and the Holy Grail, claim that they deserve much of the credit for The Da Vinci Code's success.
Written in 1982 by Michael Baigent, Richard Leigh and Henry Lincoln, it made startling claims about Jesus; notably that he not only survived the crucifixion, but moved to what is now southern France and had a child or children with Mary Magdalene.
The subsequent bloodline is protected, the book claimed, by a secret society called the Priory of Sion.
All of this is central to the plot of The Da Vinci Code, which also makes reference to The Holy Blood and the Holy Grail.
Brown's novel even includes a character called Leigh, whose surname (Teabing) is an anagram of Baigent. Furthermore, the success of Brown's novel gave The Holy Blood and the Holy Grail a huge sales boost.
However, Michael Baigent and Richard Leigh believe that's not enough. "It's not that Dan Brown has lifted certain ideas, because a number of people have done that before," explained Leigh when the writ was originally issued in 2004. "It's rather that he's lifted the whole architecture, the whole jigsaw puzzle, and hung it on to the peg of a fictional thriller."
They are suing Random House, Brown's publisher, for an alleged breach of copyright.
The action could potentially delay the release of the film in Britain and further publication of the book. And because there is little clarity on how much one author can dip into another's research, it could set a precedent for copyright law.
Leigh and Baigent say they are most concerned about their reputations as historians.
While The Holy Blood and the Holy Grail has been written off by critics as "pseudo-history" and "a masterpiece of bogus history", they still maintain that being bracketed alongside Brown, according to Baigent, "makes our work far easier to dismiss as a farrago of nonsense".
Meanwhile, the case will not only drag up arguments about the plot of The Da Vinci Code, which was so compelling as to create a cottage industry of books about the book, but will also draw further attention to the claims of alleged plagiarism that have hung around it.
Leigh and Baigent are not the only authors to claim that Brown borrowed liberally from them.
In 1983 American thriller writer Lewis Perdue wrote a book called The Da Vinci Legacy, which involved (among many other things) secret brotherhoods, a chase across Europe and the truth about the role of women in the early church.
When The Da Vinci Code was released, Perdue says, he couldn't believe the similarities. "I felt incredibly violated," he told the San Francisco Chronicle. "Ridiculous," countered Brown's publishers.
Perdue sought $84 million in damages and has catalogued his legal fight against Brown and his publishers through a blog, The Da Vinci Crock. However, despite claiming that The Da Vinci Code shared hundreds of similarities with The Da Vinci Legacy, as well as another of his books, Daughter of God, Perdue has had no success. Last year a New York judge found "no substantial similarity" between the books.
Meanwhile, the impending movie has stirred up long-running controversies.
The Catholic Church has never been pleased with a book that characterised it as willing to rewrite its own history in order to keep a hold on power, and there have already been calls from some priests for a boycott of the film.
And the Catholic organisation Opus Dei is on a charm offensive against a work that depicts it as a shadowy and threatening cult, whose members tighten a spiked cilice to their skin before going out to kill those who might unravel the conspiracy. It is not calling for a boycott, but is using the publicity to promote what it says is "the real Opus Dei".
The book has also earned the ire of American albinos. That the chief villain is a murderous, self-flagellating albino monk has not gone down well with the National Organisation of Albinism and Hypopigmentation. He's the latest Hollywood albino bad guy, it complains, to perpetuate an "evil image" and feed "bias and prejudice".