Bea got up from the table and disappeared behind the reference desk, returning minutes later with a volume of elephant-folio size.

“This one is a book of reproductions of famous maps,” she said, placing it beside the piece that Mike found inside the Audubon. “It will give you an idea of how startling the real thing is when you see all the panels joined together, as originally planned.”

She unfolded the enormous pages and spread them before us. The dozen individual engravings came together as a gigantic rectangular map of the world, separated by the seams of the individual pieces. The portion that Mike had discovered in the library’s attic, stashed under a water tank, was one from the top panel, in the third of four columns.

“It’s not only beautifully drawn,” I said, scanning the continents and islands, oceans and seas, and their relationships to one another. “But you’re right. It’s incredibly accurate for its time.”

“Men who’d never left their villages in Europe combined their own dreams of the greater world with this outpouring of information from the explorers,” Bea said. “Today, there is no more terra incognita. From your handheld GPS you can pull up a satellite image of your own backyard, or an atoll in the Pacific. These early maps charted the unknown, and they’re remarkably exciting for that reason.”

“You say there’s a complete original of this one at the Library of Congress?” Mike asked. “When was that found?”

“Don’t get too excited, Detective. More than a century ago. This sheet you stumbled over this morning is the first fresh sighting in a hundred years.”

“Tell us about the last one.”

Bea Dutton was as enthusiastic as she was knowledgeable about her cartographic history. “Have you ever heard of a German Jesuit priest named Josef Fischer?”

None of us had.

“A brilliant scholar and perhaps a bit of a rogue. There’s a very rare piece at Yale called the Vinland Map, purchased for the library there by the great philanthropist Paul Mellon. Had it been proved to be authentic, it would have shown that the Vikings predated Columbus ’s voyages to this continent by fifty years.”

“Sounds like you don’t think it’s real,” Mike said.

“Carbon-fourteen analysis dates the parchment to the 1430s, Mike, but a chemical study of the ink puts us in the 1920s. It’s on old paper-the kind you can slice right out of an ancient book, sad to say-but the ink gave it away.”

“So Father Fischer’s a fraud?”

“Well, most of us in the field think the only person he was trying to defraud-and embarrass-with his doctored map was the führer.”

“Then I’m all for the old boy already,” Mike said. “How’s that?”

“Hitler was using Norse history as Nazi propaganda. He likened the Norse to Aryans by claiming that their territorial ambitions were similar to his own empire-lust,” Bea said.

“So Fischer put the Roman Catholic Church in the mix,” Mike said. “Didn’t want the Nazis to get away with their propaganda without a little bit of religion thrown in.”

“There’s a lot of Catholic imagery in the Vinland Map,” Bea said, pointing out notations with her white glove in the same book of reproductions. “Father Fischer was so outraged by the Nazi persecution of the Jesuits that he just teased Hitler by creating this fake document. If the führer wanted to believe the Vikings led the way to the new world, Fischer wouldn’t let him have that victory unless he accepted that the Catholic Church was also along for the ride.”

“So what did Father Fischer have to do with finding my map?” Mike asked.

“See, you’ve got the fever already,” Bea said. “Your map, is it?”

Mike smiled at her. “I’ve got a lot of empty wall space in my crib. You tell me what I’m looking for and let’s go for the whole dozen panels. I’ll let you come visit any time you’d like.”

“That’s a deal, Mike,” Bea said, continuing her story. “Fischer was doing research in 1901, in a private library in a German castle. As happens with so many important discoveries in history, Fischer simply lucked upon something he’d never set out to find-in this case, a dusty portfolio in an obscure corner of a nobleman’s home. Cartographers had been searching for remnants of this particular lost map for so long that they had begun to believe the great Vespuccian model never really existed as such.”

“A complete accident, then?”

“Exactly. Prince Waldburg’s ancestors had collected maps for generations. While Fischer was studying papers of the early Norsemen in Greenland -his own personal area of interest-he came across a large manuscript that had been in the family for generations. It was a prize collection of the famous sixteenth-century globe maker named Johannes Schöner that had been acquired centuries earlier. Schöner, we figure, had purchased the Waldseemüller map of 1507 in order to incorporate its new worldview in his work so that he could use it to make his own globes more up-to-date.”

“What a find,” Mercer said.

“And especially because the twelve panels had never been assembled. Each one was carefully concealed inside the pages of this enormous folio, untouched for four centuries,” Bea said, shifting her attention back to the segment that Mike had found just a couple of hours earlier. “I’d say this looks just about faultless, too.”

“What became of the one that Father Fischer found?” Mike asked.

“It stayed in private hands-at the castle-for another hundred years. In 2003, one century and ten million dollars later, this map became the crown jewel of the Library of Congress. The universalis cosmographia.”

“What?” I asked.

“The world map of 1507 is how we know it as librarians. Universalis cosmographia secundum Ptholomaei traditionem et Americi Vespucii aliorumque lustrationes. That’s its formal name.”

“A map of the world according to the tradition of Ptolemy and the voyages of Amerigo Vespucci,” Mike said, smiling at Bea, who looked surprised by his translation ability. “You don’t think those nuns at parochial school liked me for my good behavior, do you? My Latin wasn’t half bad.”

She flipped back to the copy in her book of reproductions and again unfolded it before us.

“What are the chances that Mike’s find is a forgery?” Mercer asked.

Bea Dutton frowned. “Because of what I told you about Father Fischer?”

More likely Mercer had asked that question because of rumors about Tina Barr.

“Yeah.”

“The Vinland Map presented an entirely different issue. The Vikings were the greatest explorers of the Middle Ages-nobody disputes that. They just never made maps. Not a single one,” Bea said. “They didn’t have a concept of the world that encouraged any of them to draw diagrams, so lots of scholars were skeptical about its authenticity from the get-go. Then there’s the ink. You know how ink is made?”

I’d never given it a thought. “Actually, I have no idea.”

“It’s the reaction between iron in ferrous sulfate and tannin from oak trees. Together they oxidize on a page and literally burn the letters or drawings into the paper. Over centuries, the blackened mark starts to turn brown.”

“And the Vinland Map ink?” Mercer asked.

“Document examiners subjected it to microprobe spectroscopy, which yielded a synthetic substance-something called anatase-that was in the ink. And that wasn’t manufactured until World War One. Heave-ho to the Vikings.”

“And this?”

“Look closely at it, Mercer.” Bea pushed the tip of the antique panel closer to us and started to explain it to us. “This is exquisitely elaborate, do you see?”

There was a masterfully drawn portrait of Vespucci, holding his navigational instruments, at the top of the large panel. Below him was the upper portion of the map, representing an area that was bordered by the Arctic Ocean, and below it a landmass with tiny writing that described interior regions and portrayed the topography of the area. Behind Vespucci was a chubby-cheeked figure-the northeast wind-blowing across the frigid waters.