“Why did Pat McKinney tell me-tell the district attorney-that Tina Barr was a forger and a thief?” I asked.

“I haven’t known Minerva Hunt and her brother, Talbot, to be aligned on very many issues for as long as I’ve been around. But both of them have accused her, to the president, of stealing from the family collection in the past few months.” Jill Gibson started to lead us out of the catalog area, back to the hallway. “Quite frankly, until I looked at this call slip and made the link between Tina and Eddy Forbes, I didn’t believe it for a minute.”

Mercer was walking the length of the room, bending down to check beneath the desktops, examining the volumes along the wall.

Yuri followed behind him like a shorter, stubby shadow, protecting his turf.

At the far corner of the room there was a narrow opening.

“Where does that lead to?” Mercer asked.

“Goes nowhere. Is attic. Is only air handlers for the building,” Yuri said.

“Is there an exit up there?”

“Is nothing, I told you.”

Jill Gibson waved them off. “Nothing there. No one except engineering’s allowed in the attic. The public doesn’t have access.”

“But is there an exit from the library?” Mercer asked.

Yuri was beginning to stutter. He had a burly build, and he lurched forward, swinging his thick arms as he walked. “You-you want see? Is just roof.”

Mercer stepped aside as Yuri turned the corner, and the three of us followed. A small caged elevator was the only thing in the small dark space behind the reading room.

We all fit in it, tightly crunched together.

It was a quick ride-maybe fifteen seconds-up to the attic, literally, to the rafters below the library roof.

“Careful, miss,” Yuri said, pointing to the catwalk. “No slip.”

The space was remarkably clean and open, with giant metal pipes that circulated fresh air throughout the building.

I held on to the wooden railing as Yuri led us along the open walkway to a narrow ladder, and above it, a small hatch. Mercer climbed up behind him and stepped outside for a few seconds before rejoining us.

“Where does it go?” Mike asked.

“No egress to the street. Kind of a dead end,” Jill said. “It’s an interior courtyard, and it’s covered.”

“What if the guy was a jumper?”

“I’m afraid he’d go right through the glass roof directly below. You didn’t want to take my word for it, but that hatch is above the Bartos Forum. That’s the part of the library covered entirely in glass, to replicate the old Crystal Palace. Have you had enough, gentlemen?”

Jill seemed anxious to move us out of this space. She started along the catwalk, leading us back to the elevator.

“What are those things?” Mike asked, pointing at two huge cylindrical tanks.

I knew he was as surprised as I that the attic was so exposed, not likely to have been used to conceal a body.

“Water tanks, Mike. More than a century old. Cork-insulated barrels that sit right on top of the world’s largest plaster ceiling, with the library’s entire water supply running through them,” Jill said, pausing to look over at the giant casks. “Fire and water, Detective, are the two things a librarian has most to fear.”

Mike steadied himself on the beam and crouched down, looking under the barrels to make certain nothing was behind them.

“Hold on, folks,” he said, shimmying himself forward till his head and shoulders disappeared beneath one of the water tanks. “You more afraid of fire and water than dead bodies in your belfry?”

We all stopped in a line behind Jill Gibson. “What?” she asked in a shrill voice.

“You’re moving too fast for me, lady,” Mike said. “I just wanted to get your attention. There’s no body in here, but it looks like a nice pile of overdue library books. Might get yourself a healthy fine paid, if you come across the thief.”

Mike worked himself back out from underneath the tank, and Yuri scrambled to help him up on his feet.

“Ms. Gibson, I swear,” Yuri said. “Was here yesterday, eleven o’clock in the morning. Once every twenty-four hours, check under tank for leaks. No leaks. Was nothing there. Myself did it. Myself.”

“We’ll discuss that later, Yuri. Be still.” Jill wasn’t interested in his protestations. She stepped off the catwalk and I followed her over to where Mike had moved the small pile of books. “May I have them, please?”

“I think they’re ours for the time being,” Mike said, removing gloves from his pants pocket before he lifted the cover of the first slim volume. “Tamerlane, 1827. Edgar Allan Poe.”

“One of thirteen existing copies in the world, Detective. Fifty printed-his first published poem. A treasure, to say the least.”

“From…?”

“It was kept in a vault in the Berg Collection. That’s on the second floor, Mike. I’ll show you where.”

“Walt Whitman’s Leaves of Grass, 1860,” Mike said. “You caught a break here. It’s only a third edition.”

“That particular copy has actually got greater value than the firsts,” Jill said, nervously poised over Mike’s shoulder. “It’s called the Blue Book. Whitman kept it at his desk while he worked as a clerk at the Department of the Interior, constantly making edits in it. The secretary found it and thought it so obscene that Whitman was fired on the spot.”

The four books beneath that were larger. Three were brilliantly colored illuminated manuscripts of Petrarch’s poems, Horace’s works, and Aesop’s fables, all with spectacular calligraphy done on ancient vellum. Mike read the titles aloud to us, including the fourth one, which was an archive of the paintings of Asher Durand.

Jill Gibson exhaled. “That will raise some board eyebrows.”

“Why’s that?” Mercer asked.

“Durand was a nineteenth-century artist,” she said. “His work helped define the Hudson River School. And it’s his great painting-Kindred Spirits-which was bequeathed to us and which we sold for a fortune in 2005.”

“Over the heated objection of many of your trustees,” I said.

“That’s putting it mildly.”

“Can you give us a breakdown later of who was for and against it?” Mercer said.

“Certainly.”

Mike lifted the oversize folio that had been at the bottom of the pile. “John James Audubon, Birds of America, volume one.”

“Heads will roll,” Jill said. “That’s from the Hunt Collection-one of its jewels-and worth a king’s ransom today. If Jasper gets word that we haven’t had the ability to protect the best things he’s given us, we stand to lose all the rest.”

Mike gently lifted the cover. “Talk about the emperor’s new clothes. These birds either flew the coop, Coop, or somebody beat us to them.”

He held the book up for us to see inside, and it was clear that pages had been sliced out of it. Only blank parchment was left between the ends of the fine leather bindings.

As Mike stood up with the heavy tome in his arms, he flipped through the few remaining sheets in it. He turned the last page, and a two-foot-long fragment of a larger antique map-not bound into the old book-slipped out and fluttered to the floor.

Jill reached down for it as Mike yelled out, “Don’t touch it.”

I kneeled beside her and looked at the detailed engraving: a piece of the Asian continent, and the figure of a man standing beside a map of the world. The cartouche over his head proclaimed him to be Amerigo Vespucci.

“What’s he got to do with birds?” Mike asked.

“Nothing at all,” Jill said, steadying herself with one hand on the floor, the other clasped to her chest. “What you may be looking at is a piece of the most valuable map ever made, in a little village in France, in 1507.”

“How valuable is it? Worth enough to kill for?” he said, trying to make out the detail in the woodcut engraving.

“If all twelve sections of this puzzle actually do exist, there’s only one other map like it in the world. The price tag on it would be close to twenty million dollars.”