“I’ll give you a hundred bucks for it,” Mike said, smiling.

“I’m afraid you’d be fifty thousand pounds short.” Herrick smiled. “You must understand that with the Age of Discovery, Detective, came an explosion of new information. Sea monsters disappeared from the edges of the ocean and distant places began to take on more precise shapes. California is discovered, as you see in these subsequent volumes. For two hundred years-to the European mind-it was drawn as an island. Brilliant to watch the history of the world unfold through these documents. There was a military purpose to them, too.”

“That must have been critical,” Mike said.

“Usually a hanging offense for a merchant or soldier to share a country’s maps with a foreign power. That handsome example on the wall that you were admiring earlier,” Herrick said to me, “is the Neptune François, a collection of sea atlases commissioned by Louis XIV to give the French navy an important advantage over the British. Meticulous engravings they were-all about navigation-so soundings and rhumb lines and the markings for every little coastal port were of major importance.”

“Did it help the French in battle?”

“Well, it would have, Mr. Chapman, if the charts hadn’t been copied quite so quickly by the Dutch and distributed abroad. With the advent of printing, scholars of every nation were able to compare and revise, leading to a considerable advance in geographical knowledge.”

“Help me understand,” I asked. “What’s more valuable? The individual maps, like those hung on the walls here, or the bound atlases?”

“Ah, now you’ve hit on a point of contention. Scratch the surface of this and you’ll find real scoundrels, Ms. Cooper.”

I was looking for a stronger word to describe our perp, but I’d settle for some direction instead.

“Unlike rare books,” Herrick said, “maps were not greatly prized by collectors until thirty or forty years ago. Lord Wardington’s a perfect example. The family amassed books for generations, going back over four hundred years. He focused his attention on maps and created what was indisputably the world’s best private collection in the last four decades.”

“Why the disparity?”

Herrick pursed his lips and frowned. “Indvidual maps-the kind that sailors and traders and explorers used every day-were just utilitarian pieces of paper. Not many were considered works of art, with elaborate decorations and fine calligraphy-the kind that wind up bound in atlases. They were essentially untethered documents to be used in their own time-not carefully maintained, without any record of their provenance-just meant to get the traveler or the sailor from one place to another.

“The better maps wound up in books-printed, then hand-colored, and bound in all of the wonderful ways you see in collections. They were only sold separately when the books were damaged. You want to point a finger at the enemy?” he said, chuckling softly. “It’s the modern dealers.”

“Dealers?” I asked.

“They’re the atlas-breakers. They’re the ones who manipulate the market, trying to keep up with old-fashioned supply and demand.”

“What’s an atlas-breaker?”

“Remember I told you that this was a purely visual passion, not a scholarly one?” Herrick said. “The desirability of old maps-out of books and on the walls-was strictly a result of the fact that fashionable interior designers discovered how attractive they are, back in the 1970s and ’80s. English country style, if you will. The maps became more highly sought after than the books that held them, so dealers started hoarding the atlases and dismembering them. Taking the maps out and selling them separately was far more profitable than finding one buyer for the whole book.”

“Are there many of these dealers around New York?” Mike asked.

“You’re both too young to have known Book Row,” Herrick said. “ Fourth Avenue, between Union Square and Astor Place, was a bibliophile’s paradise for almost a hundred years. All that’s left of it these days is the Strand. So, in fact, there are only a handful of serious dealers at this point, working in the price range we’re talking about. I can tell you exactly who they are, if that’s what you need.”

“I think what we need is to figure out where Tina Barr fits in this picture,” I said. “What kind of person is she?”

“I can’t help you there. I only know her professionally. She’s incredibly well trained and has a great eye for detail. That’s one she finished for me just last week.”

I walked to the wall between two tall windows and studied the minuscule calligraphy on another exquisitely rendered old map.

“Saxton’s cartographic survey of England and Wales,” Herrick said, “commissioned by Elizabeth the First.”

“Is Tina capable of reproducing something as beautiful as this?”

“These days, Ms. Cooper, digital processing would make it possible for almost anyone to reproduce documents such as that one.”

“I mean, a copy good enough to fool-well, to fool a dealer or a collector.”

“Are you talking about a forgery? Heavens, no, Ms. Cooper. To begin with, one would have to have the proper vellum, which would be pretty difficult to come by these days. The best quality vellum was made from the skins of unborn animals. In England, you know, we still print our Acts of Parliament on it, but you’ll never find something that could be dated and matched to the original. On top of that, she’d have to be a first-rate artist, not just a meticulous restorer. Then I’d say we’d need to give her three or four years to work on it.”

“What is it that Tina did on the map you started her with?”

“Minor repairs, mostly. Decades ago, when maps were mounted for display-like this one was, in Hampton Court-they were first backed with muslin. The glue that held it in place was very destructive. So Tina removed the backing, cleaned up the tears and discoloration, and deacidified it.”

“Where did she do the work?”

“There’s a state-of-the-art facility in the public library-the Goldsmith Conservation Laboratory. She did it there.”

“Are you on the board of the library?” Mike asked.

“No, Mr. Chapman, but I make handsome contributions. You’ll find I’m quite welcome there.”

“You must have a system for doing background checks on your employees,” I said. “I assume you don’t just meet a conservator and invite him in with free access to possessions as valuable as yours.”

Herrick stood up and leaned against the desk. “There’s a very serious vetting process, and Tina passed with flying colors. I never considered her a security risk.”

“There are people at the library who think she-”

“People at the library should take their heads out of their books and stop pointing fingers at the worker bees. Every time there’s been a major problem, it’s a trustee or a donor who was responsible.”

“What do you mean?” I asked.

“All the new money on the board-hedge fund managers and the like who think that if they splash enough cash around they can buy themselves some instant class-it’s created considerable tension at the library. There’s a man called Jonah Krauss waiting like a vulture for that last great dame to die-the one before Brooke Astor-so he can sell some of her collection.”

Mike was making notes of the names.

“And I can’t think why they’d go after Tina Barr when the real map thief was paroled just a few months ago.”

“The real map thief?” I asked.

“Eddy Forbes, Ms. Cooper. The chap Minerva Hunt was in bed with,” Herrick said. “I don’t mean that literally, but I don’t doubt for a minute that she subsidized his travels.”

“What travels?”

“Eddy Forbes flooded the market with stolen goods, Detective. Some of the finest maps the world has ever seen, stolen right from under the noses of all the brass at the public library, on Jill Gibson’s watch at the Beinecke, from the Boston Library, the British Reading Room, The Hague-shall I go on or do you get my point?”