THE book cost $2 million at auction, but large sections are unreadable.
Some of its 348 pages are torn or missing and others are covered with sprawling purple patches of mildew. Sooty edges and water stains indicate a close escape from a fire.
"This manuscript is, by far, the worst of any manuscript I've ever seen," said William Noel, curator of manuscripts for the Walters Art Museum in Baltimore, where it now resides. "It's a book that is on its last legs."
The sheepskin parchment originally contained a 10th century Greek text, which was erased by a 13th century scribe who replaced it with prayers. Seven hundred years later, a forger painted gilded pictures of the Evangelists on top of the faded words.
Underneath it all, however, is an exceptional treasure -- the oldest surviving copy of works by the ancient Greek mathematician and engineer Archimedes of Syracuse, who lived in the 3rd century BC.
About 80% of the text had been transcribed and translated in the 1910s after it was rediscovered in an Istanbul monastery, but since then much of it became unreadable again because of deterioration.
Fully deciphering its mysteries has had to wait for advanced technologies, some of which had never been applied to ancient manuscripts.
The unusual cast of detectives includes not only the imaging specialists who helped photograph the Dead Sea Scrolls, but also a Stanford University physicist who studies trace metals in spinach with a particle accelerator.
Together, they have been carrying out one of the most remarkable "salvage jobs" in the history of codicology, the study of ancient manuscripts.
Archimedes, it turns out, is only one secret of the text.
AMONG the mathematicians of antiquity, Archimedes was one of the greatest and most cunning.
He was one of the earliest to devise ways to calculate the area beneath curves and was the first to prove that a circle's circumference and diameter are related by the constant pi. He developed the Archimedes Screw to lift water and invented deadly devices, such as the Claw of Archimedes, which was designed to grapple enemy warships.
Archimedes died in 212 BC, when Syracuse was sacked by the Romans. Legend holds that he was drawing figures in the sand. "Don't disturb my circles," he supposedly told the soldier who killed him.
Knowledge of Archimedes' work is derived from three books.
Codex A, transcribed around the 9th century, contained seven major treatises in Greek. Codex B, created around the same time, had at least one additional work by Archimedes and survived only in Latin translation.
Codex C has been an enigma.
It was originally copied down in 10th century Constantinople, now known as Istanbul. Three centuries later, the manuscript was in Palestine. By then, it was no longer a precious vestige of ancient learning but an obscure text that could be put to better use as a prayer book.
A scribe began by unbinding the pages. He washed them with citrus juice or milk and sanded them with a pumice stone. He cut the sheets in half, turned them 90 degrees and stitched the new book down the middle.
The scribe wrote prayers over the blank pages. Codex C had become a "palimpsest" -- a recycled book.
The book eventually was brought back to Constantinople, where it sat until the 1890s, when a Greek scholar wrote down a fragment of erased text that he was able to read.
That fragment was brought to the attention of Danish philologist Johan Ludvig Heiberg in 1906, then the foremost authority on Archimedes. Armed with a magnifying glass, he translated everything he could read, publishing his work in 1910.
The palimpsest disappeared amid the chaos of World War I, only resurfacing in 1998, when a French family named Guersan offered it for auction at Christie's in New York. An anonymous book collector paid $2 million and deposited it at the Walters Art Museum for conservation.
Mold had attacked much of the manuscript, and four forged paintings of the Evangelists made in the 20th century covered some of its most important pages.
"That was our worst nightmare," said Abigail Quandt, senior conservator of rare books and manuscripts at the Walters Art Museum.
ROGER L. Easton Jr., a 56-year-old imaging specialist at the Rochester Institute of Technology, had just come off his success revealing hidden text in the Dead Sea Scrolls.
Christie's had commissioned him to make ultraviolet images of the palimpsest for the auction catalog, and now he offered his help to the museum.
Easton and his colleagues began their work in 2000. They tinkered with different methods for capturing the image with the ultraviolet light, which makes the parchment glow more whitish.
They then merged those images with another set taken under a tungsten light, which enhanced the reddish hue of the Archimedes text. The resulting "pseudocolor" image made it easier to distinguish the black prayer book writing from the burnt sienna words of Archimedes.
Using this painstaking method, Easton and his team took two years to uncover another 15% of the text.