"Five letters," Sophie blurted.

Langdon was impressed. Teabing had just finished writing out the entire twenty-two-letter Hebrewalphabet -- alef-beit -- from memory. Granted, he'd used Roman equivalents rather than Hebrewcharacters, but even so, he was now reading through them with flawless pronunciation.

"Remember, of course," he added, "that Hebrew is normally written in the opposite direction, but we can just as easily use Atbash this way. Next, all we have to do is create our substitution scheme by rewriting the entire alphabet in reverse order opposite the original alphabet."

Teabing nodded and began writing again. "Okay, here is the proper spelling of Baphomet in Hebrew letters. I'll sketch in the missing vowels for clarity's sake. B a P V o M e Th"

A B G D H V Z Ch T Y K L M N S O P Tz Q R Sh Th "Alef, Beit, Gimel, Dalet, Hei, Vav, Zayin, Chet, Tet, Yud, Kaf, Lamed, Mem, Nun, Samech, Ayin, Pei, Tzadik, Kuf, Reish, Shin, and Tav." Teabing dramatically mopped his brow and plowed on. "Informal Hebrew spelling, the vowel sounds are not written. Therefore, when we write the word Baphomet using the Hebrew alphabet, it will lose its three vowels in translation, leaving us --"

Sophie wrote the first half of the alphabet from left to right, and then, beneath it, wrote the second half, right to left. "Crypt analysts call it the fold-over. Half as complicated. Twice as clean."

"There's an easier way," Sophie said, taking the pen from Teabing. "It works for all reflectional substitution ciphers, including the Atbash. A little trick I learned at the Royal Holloway."

Teabing eyed her handiwork and chuckled. "Right you are. Glad to see those boys at the Holloway are doing their job."

Looking at Sophie's substitution matrix, Langdon felt a rising thrill that he imagined must have rivaled the thrill felt by early scholars when they first used the Atbash Cipher to decrypt the now famous Mystery of Sheshach.

For years, religious scholars had been baffled by biblical references to a city called Sheshach. The city did not appear on any map nor in any other documents, and yet it was mentioned repeatedly in the Book of Jeremiah -- the king of Sheshach, the city of Sheshach, the people of Sheshach.

ABGDHVZChTYKThShRQTzPOSNML

Finally, a scholar applied the Atbash Cipher to the word, and his results were mind-numbing.

The cipher revealed that Sheshach was in fact a code word for another very well-known city. The decryption process was simple.

"Inches, Robert," Teabing said. He glanced over at Sophie and smiled. "You ready?"

Sheshach, in Hebrew, was spelled: Sh-Sh-K.

The mysterious city of Sheshach was revealed as the city of Babel, and a frenzy of biblical examination ensued. Within weeks, several more Atbash code words were uncovered in the Old Testament, unveiling myriad hidden meanings that scholars had no idea were there.

B-B-L, in Hebrew, spelled Babel.

Sh-Sh-K, when placed in the substitution matrix, became B-B-L.

She nodded.

"We're getting close," Langdon whispered, unable to control his excitement.

"Okay, Baphomet in Hebrew without the vowels reads: B-P-V-M-Th. Now we simply apply your Atbash substitution matrix to translate the letters into our five-letter password."Langdon's heart pounded. B-P-V-M-Th. The sun was pouring through the windows now. He looked at Sophie's substitution matrix and slowly began to make the conversion. B is Sh… P is V…

Teabing was laughing. "Quite literally!"

"Drumroll, please. Here is your password." He showed them what he had written. Sh-V-P-Y-A

"Good God!" His face went white.

"You won't believe this." Teabing glanced at Sophie. "Especially you."

Langdon didn't recognize it either.

Sophie scowled. "What is it?"

"This is… ingenious," he whispered. "Utterly ingenious!" Teabing wrote again on the paper.

Teabing was grinning like a schoolboy at Christmas. "And the Atbash Cipher reveals…" He stopped short.

"What's wrong?" Sophie demanded.

"What do you mean?" she said.

Teabing's voice seemed to tremble with awe. "This, my friend, is actually an ancient word of wisdom."

Sophie looked at the word and then at the dial. Immediately she realized Langdon and Teabing had failed to see a serious glitch. "Hold on! This can't be the password," she argued. "The cryptex doesn't have an Sh on the dial. It uses a traditional Roman alphabet."

Langdon's head snapped up.

Langdon read the letters again. An ancient word of wisdom frees this scroll. An instant later he got it. He had newer seen this coming. "An ancient word of wisdom!"

"SVFYA?" she thought, puzzled.

"Read the word," Langdon urged. "Keep in mind two things. In Hebrew, the symbol for the sound Sh can also be pronounced as S, depending on the accent. Just as the letter P can be pronounced F."

"Genius!" Teabing added. "The letter Vav is often a placeholder for the vowel sound O!"

Sophie again looked at the letters, attempting to sound them out. 'S…o…f…y…a."

Sophie suddenly missed her grandfather immensely. He encrypted the Priory keystone with my name. A knot caught in her throat. It all seemed so perfect. But as she turned her gaze to the five lettered dials on the cryptex, she realized a problem still existed. "But wait… the word Sophia has six letters."

Teabing's smile never faded. "Look at the poem again. Your grandfather wrote, 'An ancient word of wisdom.'"

"Yes?" Teabing winked. "In ancient Greek, wisdom is spelled S-O-F-I-A."

Langdon was nodding enthusiastically. "Yes! Sophia literally means wisdom in Greek. The root of your name, Sophie, is literally a 'word of wisdom.'"

She heard the sound of her voice, and could not believe what she had just said. "Sophia? This spells Sophia?"