Experts agree: Dan Brown got most of his facts wrong.
Religion scholars have been whacking "The Da Vinci Code" like a low-hanging piñata. The swings have come from establishment Christianity - the Vatican and the Archbishop of Canterbury - and from the fringes of the faith - a member of the liberal Jesus Seminar and the agnostic historian Bart Ehrman.
At least 44 books debunking "The Da Vinci Code" are for sale at Amazon.com, several written by serious academics or well-known pastors. And with the movie starring Tom Hanks scheduled to open next week, surely more are in the pipeline.
All of which leaves this question unanswered: Why bother?
Why do serious people take the book so seriously? "The Da Vinci Code" is fiction. A novel. It says so right on the cover. That means the writer made stuff up.
The critics have at least 46 million reasons to want to set the record straight. That's the number of copies Brown has sold worldwide. And the movie may play to an even larger audience.
But popularity alone can't explain the cascade of criticism, even if you figure many of the authors are trying to sell their own books by hitching their wagon to Brown. "Star Wars" was an international blockbuster, and physicists didn't fill bookshelves explaining there's no such thing as a light saber.
George Lucas never claimed there was anything real in "Star Wars," though. Brown has tried to have it both ways. Charles Gibson, host of ABC-TV's "Good Morning America," pressed the author on the point in 2003.
"If you were writing it as a nonfiction book," Gibson asked, "how would it have been different?"
"I don't think it would have," replied Brown, who almost never grants interviews.
"I began the research for 'The Da Vinci Code' as a skeptic...
. (A)fter numerous trips to Europe, about two years of research, I really became a believer... "
A believer in what? The book's plot revolves around a centuries-old conspiracy to hide the marriage of Jesus and Mary Magdalene and their descendants. The conspirators included Sir Isaac Newton and Leonardo Da Vinci, who cleverly hid clues to the secret in his paintings. (Hence the title.)
The very first sentence in the book implies this is more than a mere tale. "Fact: The Priory of Sion - a European secret society founded in 1099 - is a real organization." This arcane society, according to Brown's telling, has been the keeper of the secret about Jesus and Magdalene.
But the "fact" is almost certainly wrong. Last month, "60 Minutes" piled up evidence that a Frenchman - an anti-Semite with a history of criminal fraud - "created" the Priory as a hoax in the 1950s.
The book reeks of truthiness and smartiness, the appearance of being truthful and smart without necessarily being either. The protagonist is a Harvard professor (in a department that doesn't exist). The fast-moving plot is propelled by a series of clever puzzles based on famous works of art.
But the debunking books list factual errors large and small:
The glass pyramid at the Louvre has 673 glass panes, not 666. The Dead Sea Scrolls were written by Jews and say nothing about Jesus. They were discovered in 1947, not the 1950s.
The irrational number Phi is not precisely equal to 1.618.
If the figure to the left of Jesus in "The Last Supper" is really Mary Magdalene, as the book claims, then Leonardo left out an apostle. If it's really John, as most art historians claim, Leonardo was neither the first nor the only artist to paint him as a beardless, long-haired young man.
Brown's best "proof" of a romance between Jesus and Mary Magdalene comes from the Gospel of Philip, one of the Gnostic gospels. In "The Da Vinci Code," the quote reads: "The companion of the Savior is Mary Magdalene. Christ loved her more than all the disciples and used to kiss her often on her mouth."
But Ehrman, a text scholar, says the only manuscript we have of that gospel is full of holes. And that all we have of that passage is "The companion of the (gap) Mary Magdalene (gap) more than (gap) the disciples (gap) kiss her (gap) on her (gap)."
If Brown can't get inarguable facts right, the experts say, what faith can readers place in his conclusions about the nature of Christianity?
Some critics say they're intent on tearing down the credibility of the book because many people, mostly ignorant of what is known of the early years of Christianity, accept Brown's fictions as gospel truth.
"In our experience, readers are taking it as true," said Ehrman, a religious studies professor at the University of North Carolina and the author of "Truth and Fiction in The Da Vinci Code." "Historians care about what happened in the past, and it's important... to separate the fact from the fiction."
The U.S. Conference of Catholic Bishops is so concerned about the book that it's created a Web site, jesusdecoded.com, with official Catholic responses to the issues Brown raises in the book.
"A bishop came to me and said, 'I never had to read a novel because my parishioners came up to me to say I should read it,'" said the Rev. Francis Maniscalco, communications director for the conference.
Brown is muddling people's thinking in ways that could shake faith and affect the reputation of real institutions, said the Rev. Timothy Friedrichsen, a New Testament professor at Catholic University.
"Brown's work only confuses the matter, and in this reader's opinion, intentionally," he said. But Friedrichsen joked that Brown need not fear worldly retribution from the Vatican.
"He can, however, look at the bright side: The dark chapter in the church's history of the Inquisition is long past."
There is some evidence that readers are buying the bunkum.
Last year, pollster George Barna reported that 53 percent of American adults who finished the book said it had been helpful in their "personal spiritual growth and understanding."
Whatever that means.
A Canadian survey commissioned last year by National Geographic showed that 32 percent who read "The Da Vinci Code" believed its theories.
And last week, in a Catholic Digest poll, 73 percent of American Catholics said the book "did not affect their faith or opinion of the church in any way." Which means that up to 27 percent - about 14 million Catholics - may be vulnerable to having their faith affected by Brown's tale.
The author shrugs off his critics.
"It's a book about big ideas, you can love them or you can hate them," he said in a speech in Portsmouth, N.H., last month. "But we're all talking about them, and that's really the point."
That discussion is good news, even from the critics' perspective.
"As a scholar I'm very grateful to Dan Brown. People like me are in demand right now in a way we have never been before," said Gail Streete, a religious studies professor and expert on Mary Magdalene at Rhodes College in Memphis. "Most of the time nobody pays any attention to what we do."
Brown has made Darrell Bock of Dallas a successful author on several continents. Bock, a professor of New Testament studies at Dallas Theological Seminary, is the author of "Breaking the Da Vinci Code."
The book has hit best-seller lists in Australia, Brazil and Germany, he said. He's become a sought-after speaker at church and college events.
"People are finally engaging these topics, and want to engage on the level of substance," he said.
Robert Price is a member of the Jesus Seminar, an academic group that has tried to sift the Gospels for "historical truth" by rejecting accounts of miracles and other supernatural elements. He's also the author of "The Da Vinci Fraud." He's not angry at Brown for casting doubt on the official histories of Christianity. He's mad, he said, because Brown did it so badly.
For Price, the success of "The Da Vinci Code" is evidence that people are willing to entertain doubts about theology.
"It must mean people are a lot more open-minded than I ever figured they would be about it," he said.
The Rev. Kendall Harmon, an Episcopal theologian in South Carolina, compares Brown to Celsus, a second-century critic of Christianity. Celsus inspired early Christians into thoughtful responses, he said.
"A Christian who reads 'The Da Vinci Code' and can explain to his or her friends why 'The Da Vinci Code' is wrong is a more effective Christian," he said. "As Celsus strengthened the early church, so Dan Brown is strengthening us."