In the Louvre, Robert Langdon's thoughts turned back to Saunière, the chief curator. A remarkable man, Langdon mused. Shot in the stomach, with just minutes to live, Saunière had managed to arrange a trail of clues for Langdon to follow and—incredibly—still had time to complete the crossword in Le Monde before he died.

Now Sophie had discovered another clue in the museum bookstore. On the floor, scrawled in Saunière's own blood, was a set of vertical lines with corresponding numbers. Below that was another string of numbers, interspersed with dashes. Beneath it all, a cryptic message: "PIE CAN SNUB"

"What does it mean?" Sophie asked. "What kind of pie?"

"The message is an anagram," Langdon said. He took out a notebook and pen and rearranged the letters of "PIE CAN SNUB" to read "UPC ISBN EAN."

"That makes less sense than the first message," Sophie said. "And those lines look like... like prison bars."

"You're close," Langdon said. "Not prison bars, but bar codes!"

"A UPC! I must be blind," she said. "I see them all the time, on everything from adult diapers to Dippity-Doo. Of course, they aren't usually printed in blood."

"That's not a Universal Product Code," Langdon said. He pointed at the floor. "You see that set of numbers, separate from the bar code? That's an ISBN—International Standard Book Number. It's specific to the publishing industry and identifies books and book-related products. Those 10 digits tell you the country of manufacture, the publisher, the title—everything."

"You're amazing!" she said. "How do you know all this?"

"You forget, I'm a published author." Langdon's latest book, Holy Grail—Holy Cow!, was already climbing bestseller lists. "The bar code Saunière drew corresponds to a 13-digit EAN—European Article Number. Notice anything about it?"

Sophie stared at the symbol. "Nope."

Good thing she's cute, Langdon thought. "The EAN includes the ISBN," he told her. "It's called 'ISBN-13.' "

What's the significance of the first three numbers: 978?" she asked.

"You're familiar with 666? From the Book of Revelation? The Mark of the Beast?"

"Yes...."

"Well, this has nothing to do with that. Those digits indicate a country of origin. The prefix 978 identifies the country as Bookland. 978 is also an area code in Massachusetts," he added.

"The things you know! But wait a minute—there is no such country as Bookland."

"You won't find it on any map," Langdon said, "but it exists all right—at least in the minds of a handful of powerful people in the publishing industry."

"Who are they?"

"BISG," Langdon said. "Book Industry Study Group—an innocuous-sounding name for a very mysterious organization. Not much is known about them. We believe the founders were once Freemasons who were expelled for actually doing masonry—patios, retaining walls, that sort of thing. They formed a splinter group, and began to infiltrate the book business. Today their tentacles reach into every area of publishing."

"And Bookland?"

"A shadow country," Langdon said. "If BISG has its way, Bookland will one day encompass the entire world. All books everywhere will be bought and sold within its borders."

"It's insidious! Can anything be done?"

Langdon shook his head. "I'm afraid it started more than a year ago. They called it 'Sunrise 2005'—the dawn of a New Age. Nothing can stop it now. By January 1, 2007, ISBN-13 will be the dominant bar code in the publishing world. Forever."

"Robert, I'm scared."

Langdon pointed again. "That ISBN and EAN denote the same product. Don't you see? Saunière was trying to lead us to a specific book!" He grabbed the scanning gun, stretched it to the scrawled symbol, and scanned the bloody bar code. Then he hurried behind the counter and stared at the display.

"Of course!" he cried. "It's the answer to a question I put to Saunière before he died!"

"Was it about Leonardo?" Sophie asked, hurrying to join him. "Opus Dei? The Holy Grail?"

"No," Langdon said. "I asked him if he knew a good airplane read for my flight back to Boston."

Open-mouthed, Sophie stared at the words on the screen:

The Da Vinci Code by Dan Brown