The DaVinci Code has been atop The New York Times bestseller list and Amazon.com since it was released three years ago. Not even the release of a new John Grisham novel knocked it off. It inspired a one-hour ABC News special. Now it's a major motion picture starring Tom Hanks.

At first glance the plot isn't anything that stands out above normal mystery fare. It starts off with the murder of a curator at the Louvre in Paris, leads to a trail of clues found in the work of Leonardo DaVinci, and the discovery of a centuries-old secret society. It's a page-turner. But that's not what has grabbed our attention. It's that the clues of Leonardo's work and the mission of the secret society revolve around the Holy Grail.

This Holy Grail is not put forward as what we traditionally think of as the Holy Grail, the chalice that Jesus used during the Last Supper. The novel identifies the Holy Grail as the bloodline of Jesus and suggests that Mary Magdalene was the wife of Jesus and the mother of his child. ...