espite containing what many have called “the most beautiful room in the world,” the Library of Congress is known less for its breathtaking splendor than for its vast collections. With over five hundred miles of shelves—enough to stretch from Washington, D.C., to Boston—it easily claims the title of largest library on earth. And yet still it expands, at a rate of over ten thousand items per day.

As an early repository for Thomas Jefferson’s personal collection of books on science and philosophy, the library stood as a symbol of America’s commitment to the dissemination of knowledge. One of the first buildings in Washington to have electric lights, it literally shone like a beacon in the darkness of the New World.

As its name implies, the Library of Congress was established to serve Congress, whose venerated members worked across the street in the Capitol Building. This age-old bond between library and Capitol had been fortified recently by the construction of a physical connection—a long tunnel beneath Independence Avenue that linked the two buildings.

Tonight, inside this dimly lit tunnel, Robert Langdon followed Warren Bellamy through a construction zone, trying to quell his own deepening concern for Katherine. This lunatic is at her lab?! Langdon didn’t even want to imagine why. When he had called to warn her, Langdon had told Katherine exactly where to meet him before they hung up. How much longer is this damned tunnel? His head ached now, a roiling torrent of interconnected thoughts: Katherine, Peter, the Masons, Bellamy, pyramids, ancient prophecy . . . and a map.

Langdon shook it all off and pressed on. Bellamy promised me answers.

When the two men finally reached the end of the passage, Bellamy guided Langdon through a set of double doors that were still under construction. Finding no way to lock the unfinished doors behind them, Bellamy improvised, grabbing an aluminum ladder from the construction supplies and leaning it precariously against the outside of the door. Then he balanced a metal bucket on top. If anyone opened the door, the bucket would crash loudly to the floor.

That’s our alarm system? Langdon eyed the perched bucket, hoping Bellamy had a more comprehensive plan for their safety tonight. Everything had happened so fast, and Langdon was only now starting to process the repercussions of his fleeing with Bellamy. I’m a fugitive from the CIA.

Bellamy led the way around a corner, where the two men began ascending a wide staircase that was cordoned off with orange pylons. Langdon’s daybag weighed him down as he climbed. “The stone pyramid,” he said, “I still don’t understand—”

“Not here,” Bellamy interrupted. “We’ll examine it in the light. I know a safe place.”

Langdon doubted such a place existed for anyone who had just physically assaulted the director of the CIA’s Office of Security.

As the two men reached the top of the stairs, they entered a wide hallway of Italian marble, stucco, and gold leaf. The hall was lined with eight pairs of statues—all depicting the goddess Minerva. Bellamy pressed on, leading Langdon eastward, through a vaulted archway, into a far grander space.

Even in the dim, after-hours lighting, the library’s great hall shone with the classical grandeur of an opulent European palace. Seventy-five feet overhead, stained-glass skylights glistened between paneled beams adorned with rare “aluminum leaf”—a metal that was considered to be more precious than gold at one time. Beneath that, a stately course of paired pillars lined the second-floor balcony, accessible by two magnificent curling staircases whose newel posts supported giant bronze female figures raising torches of enlightenment.

In a bizarre attempt to reflect this theme of modern enlightenment and yet stay within the decorative register of Renaissance architecture, the stairway banisters had been carved with cupidlike putti portrayed as modern scientists. An angelic electrician holding a telephone? A cherubic entomologist with a specimen box? Langdon wondered what Bernini would have thought.

“We’ll talk over here,” Bellamy said, leading Langdon past the bulletproof display cases that contained the library’s two most valuable books—the Giant Bible of Mainz, handwritten in the 1450s, and America’s copy of the Gutenberg Bible, one of only three perfect vellum copies in the world. Fittingly, the vaulted ceiling overhead bore John White Alexander’s six-panel painting titled The Evolution of the Book.

Bellamy strode directly to a pair of elegant double doors at the center rear of the east-corridor wall. Langdon knew what room lay beyond those doors, but it seemed a strange choice for a conversation. Notwithstanding the irony of talking in a space filled with “Silence Please” signs, this room hardly seemed like a “safe place.” Located dead center of the library’s cruciform-shaped floor plan, this chamber served as the heart of the building. Hiding in here was like breaking into a cathedral and hiding on the altar.

Nonetheless, Bellamy unlocked the doors, stepped into the darkness beyond, and groped for the lights. When he flipped the switch, one of America’s great architectural masterpieces seemed to materialize out of thin air.

The famous reading room was a feast for the senses. A voluminous octagon rose 160 feet at its center, its eight sides finished in chocolate-brown Tennessee marble, cream-colored Siena marble, and apple-red Algerian marble. Because it was lit from eight angles, no shadows fell anywhere, creating the effect that the room itself was glowing.

“Some say it’s the most striking room in Washington,” Bellamy said, ushering Langdon inside.

Maybe in the whole world, Langdon thought as he stepped across the threshold. As always, his gaze first ascended straight up to the towering central collar, where rays of arabesque coffers curled down the dome to an upper balcony. Encircling the room, sixteen bronze “portrait” statues peered down from the balustrade. Beneath them, a stunning arcade of archways formed a lower balcony. Down at floor level, three concentric circles of burnished wood desks radiated out from the massive octagonal circulation desk.

Langdon returned his focus to Bellamy, who was now propping the room’s double doors wide open. “I thought we were hiding,” Langdon said, confused.

“If anyone enters the building,” Bellamy said, “I want to hear them coming.”

“But won’t they find us instantly in here?”

“No matter where we hide, they’ll find us. But if anyone corners us in this building, you’ll be very glad I chose this room.”

Langdon had no idea why, but Bellamy apparently wasn’t looking to discuss it. He was already on the move toward the center of the room, where he selected one of the available reading desks, pulled up two chairs, and flipped on the reading light. Then he motioned to Langdon’s bag.

“Okay, Professor, let’s have a closer look.”

Not wanting to risk scratching its polished surface with a rough piece of granite, Langdon hoisted his entire bag onto the desk and unzipped it, folding the sides all the way down to reveal the pyramid inside. Warren Bellamy adjusted the reading lamp and studied the pyramid carefully. He ran his fingers over the unusual engraving.

“I assume you recognize this language?” Bellamy asked.

“Of course,” Langdon replied, eyeing the sixteen symbols.

Known as the Freemason’s Cipher, this encoded language had been used for private communication among early Masonic brothers. The encryption method had been abandoned long ago for one simple reason—it was much too easy to break. Most of the students in Langdon’s senior symbology seminar could break this code in about five minutes. Langdon, with a pencil and paper, could do it in under sixty seconds.

The notorious breakability of this centuries-old encryption scheme now presented a couple of paradoxes. First, the claim that Langdon was the only person on earth who could break it was absurd. Second, for Sato to suggest that a Masonic cipher was an issue of national security was like her suggesting our nuclear launch codes were encrypted with a Cracker Jack decoder ring. Langdon was still struggling to believe any of it. This pyramid is a map? Pointing to the lost wisdom of the ages?

“Robert,” Bellamy said, his tone grave. “Did Director Sato tell you why she is so interested in this?”

Langdon shook his head. “Not specifically. She just kept saying it was an issue of national security. I assume she’s lying.”

“Perhaps,” Bellamy said, rubbing the back of his neck. He seemed to be struggling with something. “But there is a far more troubling possibility.” He turned to look Langdon in the eye. “It’s possible that Director Sato has discovered this pyramid’s true potential.”