IT is a publishing phenomenon that has sparked controversy. Now the film version of The Da Vinci Code is attempting to reduce the offence caused to Catholics.
Sony Pictures, the studio behind the film, which stars Tom Hanks and Ian McKellen, is reported to have been so concerned about offending the devout that it has consulted Catholic and other Christian specialists on how it might alter the plot of the novel.
Film officials have held talks with Catholic groups and other organisations, despite author Dan Brown insisting that "it's only a novel and therefore a work of fiction".
The Catholic League is calling for the film's Oscar-winning director Ron Howard to include a disclaimer, acknowledging that the movie is fiction.
The Da Vinci Code, which is being filmed this year, is based on a novel that has sold 25 million copies worldwide.
Among its more controversial claims is that Jesus married Mary Magdalene, a former prostitute, and that she bore him a child. This has been denounced as virulently anti-Catholic and a risible hoax.
Opus Dei, the Catholic organisation, is particularly concerned about its own depiction, because it is a central villain in the book.
Its members are depicted acting unethically for the sake of God, the Church or Opus Dei, whereas the organisation is a Catholic institution that adheres to Catholic doctrine and condemns immoral behaviour.
Spokesman Brian Finnerty said the novel portrayed Opus Dei in a completely inaccurate way. "We wrote to the studio, expressing our concern. They sent back a reply that was polite but non-committal, but Opus Dei is completely unlike the portrayal in the novel."
The studio has been asked to consider whether the central premise - that Jesus had a child with Mary Magdalene - could be more ambiguous and whether the name of Opus Dei could be removed.
Condemnation of the book has been widespread. In March, the Vatican appointed a cardinal to rebut what it dismissed as lies, distortions and errors.
Sony declined to comment.