According to Harlan Coben, New York Times bestselling author, "Dan Brown is my new must-read. I loved this book. The Da Vinci Code is fascinating and absorbing-perfect for history buffs, conspiracy nuts, puzzle lovers, or anyone who appreciates a great, riveting read." Collin Hansen says that with the Da Vinci Code, Brown "captured the coveted number one sales ranking at Amazon.com, camped out for 32 weeks on the New York Times Best-Seller List and inspired a one-hour ABC news special." A film based on the book, starring Tom Hanks, is scheduled for release in May 2006.
The Wikipedia online encyclopedia states, "The Da Vinci Code is a novel written by American author Dan Brown and published in 2003 by Doubleday Fiction…The plot of the novel involves a conspiracy by the Catholic Church to cover up the true story of Jesus. This implies that the Vatican consciously knows it is living a lie, but does so to keep itself in power. The novel has helped generate popular interest in speculation concerning the Holy Grail legend and the role of Mary Magdalene in the history of Christianity. Fans have lauded the book as creative, action-packed and thought-provoking. Critics have attacked it as inaccurate and poorly written, and decry the many negative implications about the Catholic Church." Michael Gleghorn further enlightens us: "The story begins with the murder of the Louvre's curator. But this curator isn't just interested in art; he's also the Grand Master of a secret society called the Priory of Sion. The Priory guards a secret that, if revealed, would discredit biblical Christianity. Before dying, the curator attempts to pass on the secret to his granddaughter Sophie, a cryptographer, and Harvard professor Robert Langdon, by leaving a number of clues that he hopes will guide them to the truth…in Brown's novel, the [Holy] Grail is not the cup allegedly used by Christ at the Last Supper. It's rather Mary Magdalene, the wife of Jesus, who carried on the royal bloodline of Christ by giving birth to His child! The Priory guards the secret location of Mary's tomb and serves to protect the bloodline of Jesus that has continued to this day!
The book might be riveting as a mystery fiction, but it appears that Dan Brown has also been trying to "sell" it as truth. Some of the things for which Brown seems to claim historicity are: A marriage between Jesus and Mary Magdalene; The superiority of the Gnostic Gospels over the Canonical Gospels (Matt, Mark, Luke, John); That Jesus' earliest followers did not believe He was divine; The Gospels of Matthew, Mark, Luke and John were changed under the command of Constantine; The deity of Jesus was devised by the Council of Nicea in the fourth-century. Someone said that according to Brown, "almost everything our fathers taught us about Christ is false!"
Early copies of the Gospels - as much as a hundred years before the council of Nicea - do not show evidence of the supposed embellishment. AND early copies of parts of John's Gospel are available. John's gospel has strong declarations of Jesus as God - significantly before the council of Nicea or before Constantine had an opportunity (supposedly) to tamper with the Gospels. Pre-Nicene church fathers affirm the deity of Christ. For example, Ignatius wrote of "our God, Jesus the Christ." There is also testimony of non-Christians showing that Christians believe Jesus was God. It can be established satisfactorily that early Christians worshipped Jesus Christ as their Lord and God.
Some good reading to get the rest of the story is Eusebius' Ecclesiastical History and Breaking the Da Vinci Code: Answers to the Questions Everyone's Asking by Darrell Bock. Bock believes "Da Vinci" is properly fictitious entertainment rather than factual history of the Christian faith.
I found Redeeming the Da Vinci Code, written by Michael Gleghorn, to be very helpful, and my comments are greatly indebted to his online article.