That I have read the book is not a cause for celebration. It is inelegant, pedestrian writing in service of a plot that sets up cliff-hangers like clockwork, resolves them with improbable escapes and leads us breathlessly to a disappointing anticlimax. I should read a potboiler like The Da Vinci Code every once in a while, just to remind myself that life is too short to read books like The Da Vinci Code.

The Da Vinci movie, set for 2005, will be directed by Ron Howard, who should study this one for clues about what to avoid. The central weakness of the story is the absurdity of the clues, which are so difficult that no sane forefather could have conceivably believed that anyone could actually follow them. That the movie's hero, named Benjamin Franklin Gates and played by Nicolas Cage, is able to intuitively sense the occult meanings of ancient riddles and puzzles is less a tribute to his intelligence than to the screenplay supplying him with half a dozen bonus A-ha! Moments. An A-Ha! Moment, you will recall, is that moment at which a movie character suddenly understands something which, if he did not understand it, would bring the entire enterprise to a halt.

Benjamin Franklin Gates is named, of course, after the famous software millionaire. His family of historians has been scorned for generations because of its belief that a vast treasure was brought back from the Crusades by the Knights Templar and has been hidden by the Masons -- in this case, Masons who were the Founding Fathers of America. Benjamin's father, Patrick Henry Gates (played by Jon Voight and named after O. Henry), scoffs at the family legend, but his grandfather John Adams Gates (played by Christopher Plummer and named after the inventor of the toilet) gives Benjamin a clue handed down through the generations from Charles Carroll, the last surviving signer of the Declaration of Independence.

This clue, which involves the word "Charlotte," seems baffling until Benjamin has an A-Ha! and leads an expedition north of the Arctic Circle in search of a 19th century sailing ship which, he calculates, must have frozen in the ice and then been shifted miles inland by the gradual movement of the floes. To say the expedition finds the ship without much trouble is putting it mildly; Benjamin digs about a foot down into the permafrost, and then bends over and wipes clean a brass nameplate that helpfully says "Charlotte."