In October 2010, an Italian religious historian named Alberto Melloni stood over a small cherrywood box in the reading room of the Laurentian Library, in Florence. The box was old and slightly scuffed, and inked in places with words in Latin. It had been stored for several centuries inside one of the library’s distinctive sloping reading desks, which were designed by Michelangelo. Melloni slid the lid off the box. Inside was a yellow silk scarf, and wrapped in the scarf was a thirteenth-century Bible, no larger than the palm of his hand, which was falling to pieces.

“Molecules, not people, start to talk,” a researcher said, of the field of proteomics. Illustration by Alexander Glandien

The Bible was “a very poor one,” Melloni told me recently. “Very dark. Very nothing.” But it had a singular history. In 1685, a Jesuit priest who had traveled to China gave the Bible to the Medici family, suggesting that it had belonged to Marco Polo, the medieval explorer who reached the court of Kublai Khan around 1275. Although the story was unlikely, the book had almost certainly been carried by an early missionary to China and spent several centuries there, being handled by scholars and mandarins—making it a remarkable object in the history of Christianity in Asia.

Melloni is the director of the John XXIII Foundation for Religious Sciences, an institute in Bologna dedicated to the history of the Church. He had heard of the Marco Polo Bible, but he was unaware of its poor condition until a colleague spotted the crumbling book at an exhibition at the library, in 2008, and pitched a project to restore it and find out more about its past. “It was like a sort of Cinderella among the beautiful sisters,” Melloni said. Like other people accustomed to handling old texts or precious historical objects, Melloni has a special regard for what Walter Benjamin called their aura: “a strange weave of space and time” that allows for an intimation of the world in which they were made. “You have in your hand the manuscript,” Melloni said. “But also the stories that the manuscript is carrying.”

The restoration took eighteen months. Ten thousand pieces of the Bible were reassembled. In the process, Melloni was determined to subject the document to the latest scientific analysis. “We should do on this Bible the type of thing that would be done on the ‘Mona Lisa,’ ” Melloni told his colleagues. He contacted the cultural-heritage center at the Polytechnic University of Milan, the largest scientific school in Italy, to ask advice. In addition to standard conservation tools, like ultraviolet photography and infrared spectroscopy, which is used to study pigments, the experts there suggested proteomics. “It was the first time I heard the word ‘proteomic’ in my life,” Melloni recalled.

Proteomics is the study of the interaction of proteins in living things. Where genomics studies humans’ roughly twenty thousand genes, proteomics is concerned with the shifting array of proteins assembled by those genes—our biological content, more or less, from albumin, which makes up sixty per cent of our blood proteins, to beta-amyloid, a family of brain molecules that can be a potential sign of Alzheimer’s disease. Proteomics aims for completeness. The proteome of a single human cell, which might contain billions of proteins, is sometimes compared to an atlas. It can guide geneticists or drug companies to early markers of a disease, or to the precise mechanism of aging, or to promising targets for cancer treatment. The field has been made possible by spectacular advances in data analysis and in lab instruments, which become cheaper and more powerful each year. Top-of-the-line mass spectrometers now allow chemists to sort through thousands of types of proteins in a sample, and to study them, one molecule at a time.

Since 2000, proteomics has attracted the attention of a small clutch of scientists who believe that it has the potential to immensely expand our knowledge of the past. Under the right conditions, proteins can survive for millions of years. In recent years, proteomic studies of artworks and archeological remains have yielded biological information of startling clarity, revealing gossamer-thin layers of fish glue on seventeenth-century religious sculptures and identifying children’s milk teeth from pits of previously unrecognizable Neolithic bones. In 2008, researchers were able to sequence the proteins of a harbor seal that remained on the surface of six-hundred-year-old cooking pots found at an Inuit site in northern Alaska. Three years later, chemists found a hundred and twenty-six different proteins in a mammoth femur. With new proteomic techniques emerging constantly, the field has a heady, chaotic atmosphere of possibility. At a four-day conference called Ancient Proteins, held this summer in Copenhagen, presentations had titles such as “Biologics in Art: Whaaat???,” “Palaeoproteomic Analysis of Binding Media and Adhesives in Ancient Egypt,” and “Through the Looking Glass, and What Amino Acids Found There.”

Melloni arranged to have some fragments of the Bible sent to Milan. In the fall of 2011, a few pieces arrived at the laboratory of Pier Giorgio Righetti, a tall, slender chemist in his seventies, with a neat beard, like Trotsky’s. Righetti is known in the world of proteomics for his work on electrophoresis, a process that helps to sort molecules by size and by an electrical charge. He comes across as a happy man, prone to finishing his sentences with a long, high-pitched laugh. Once, when we were riding the subway together in Milan, we walked onto a platform just as the train was coming in. “Yes, yes, yes! We are lucky! We are lucky!” he yelled as he ran up to the doors as if this were the best thing to happen to him in years.

Righetti started out studying the proteins of maize, in 1971. Back then, a laboratory might spend years sequencing a single protein. “Now proteomics is like when you are looking at a starry sky,” Righetti said. Unlike the genome, which stays largely the same, an organism’s proteome changes all the time. Our cells produce different proteins when we are asleep, when we are afraid, and when we are sick. Proteins from the past are the biological remnants of a specific instant: a supper of a seal, an ailing mammoth. “It is frozen,” Righetti said. “A certain moment in the life of this fellow.”

Testing the Marco Polo Bible was the first time that Righetti had studied something old. He has an affinity, however, for subjects that are historical and romantic. His father was an elelementary schooleacher and a poet. As a boy, Righetti dreamed of studying literature, but was afraid of being poor. Alongside his chemical research, he has written two novels and is currently at work on a third, a story about the Palestinians since Biblical times. His scientific papers often have literary titles that belie their abstruse content. (A 2007 paper called “Sherlock Holmes and the Proteome” was about hexapeptide ligand libraries.) For the study of the Bible, Righetti read at least six books about Marco Polo.

In the lab, he struggled with the manuscript pieces. They were badly withered and resistant to the normal technique for removing proteins, which is done with a solvent. One evening, in desperation, a colleague of Righetti’s warmed one of the fragments in a microwave. “A bloody microwave!” Righetti said. It worked.

After running the samples through a mass spectrometer, Righetti and his team identified eight biomolecules from the Bible, which had been thought to be made from fetal lambskin. But the proteins belonged to cows, proving that the parchment was vellum—made from vealskin—and indicating, along with evidence from the text, that it was probably made in southern France sometime before 1250.

Righetti was elated to see seven-hundred-and-fifty-year-old proteins showing up clearly in the data. He described the findings in a paper, which added to the small but growing literature about the proteomics of medieval manuscripts. “We felt it was a big, big success,” he told me. But Righetti had a nagging feeling that the experiment might be a one-off. Not only have most historians not heard of proteomics, but the testing generally involves sacrificing part of the artifact, making it difficult to acquire objects to study. “Nobody would ever let you,” Righetti said. “We had the pieces sent to us from Florence because this Bible was in smithereens.”

At the end of the restoration project, Melloni flew to Beijing and presented the Bible to an audience at the library of Peking University. The air was slightly humid. When he opened the pages, they fluttered briefly, as if responding to a memory. “They had a sense of movement,” Melloni recalled. “Like they were wings.”

The day that Righetti’s paper was published, in the spring of 2012, he was at the library of the University of Zaragoza, in northern Spain. A curator had invited Righetti to look at the collection and discuss possible research. There were some medieval Bibles and an early Torah on a parchment scroll. As Righetti feared, the awkward question of destructive sampling came up. Although the samples required for proteomic analysis can be as small as a pinhead, many people entrusted with priceless objects are, by instinct and by training, deeply averse to giving them up. “Conservators are well named. They are very conservative,” Matthew Collins, the chair of paleoproteomics at the University of Cambridge, told me. In Zaragoza, Righetti told the librarian that he was keen to study the Torah. “I asked him, ‘Could I take a tiny bit?’ ” he recalled. “That was the end of the conversation.”

Righetti was walking across the campus when his phone rang. It was Gleb Zilberstein, an inventor who works out of Rehovot, Israel. The scientists had collaborated, on and off, for more than a decade. In his own way, Zilberstein, who is forty-nine, had been thinking about the scientific analysis of literature for some time. He is a fan of Umberto Eco’s work on semiotics, which proposes multiple ways to interpret a text, and he had often wondered about the chemical interaction between an author and the pages on which he works. “Each person wants to understand cultural life things through the prism of his experience,” Zilberstein told me. “My experience is tools for analytical chemistry.”

Reading Righetti’s paper that morning, Zilberstein had been struck by an idea. His latest startup was a project to develop plastics with charged ions on their surface which would draw microbes and bacteria off other substances. He wanted to use the technology in food and drinks packaging. Zilberstein wondered if it could also be applied on works of art. In theory, researchers could use the charged plastics to remove proteins—in fact, almost any chemical—from an artifact without destroying part of it in the process. Even the most treasured documents and canvases could be analyzed for tantalizing traces that might remain on or near their surface:sweat, saliva, or signs of disease; evidence of an artist’s diet, drugs, even DNA. “You can find out what you ate, how you hurt, how the author was treated,” Zilberstein told me.

Righetti was excited. He often describes Zilberstein, who does not have a Ph.D. and has never held a formal post at a university, as a genius. “I will be honest,” Righetti said. “He is much better than me. He is much more brilliant.” On the phone in Zaragoza, he encouraged Zilberstein to pursue the idea. “Professor Righetti said, ‘O.K. Just do it,’ ” Zilberstein recalled. “Like a Nike slogan.”

Zilberstein decided to go to the State Library of Russia, in Moscow, to test his hunch. He had grown up in northern Kazakhstan, in a family of Soviet military engineers. His grandmother Sara built airplanes; his father, Victor, made torpedoes. As a student, in the late eighties, Zilberstein spent two years in Moscow doing his military service. He avoided most of his infantry duties by designing bulletproof vests and inventing a new kind of paint for crash-test dummies which changed color on impact. He also killed a lot of time in the city’s theatres and concert halls. “I think it was the crucial period for me,” he said. He liked to spend his afternoons in the state library.

Soon after graduating from Novosibirsk State University, with a degree in physics, in 1994, Zilberstein immigrated to Israel. But he is often in Moscow, and he knew that the library’s collections of nineteenth- and twentieth-century manuscripts had a serious problem. When cheap, mass-produced paper was invented, in the nineteenth century, it transformed printing and publishing. But the paper was slightly acidic, and, over time, it darkened and became brittle. In late 2012, Zilberstein visited the state library and proposed his technology as a way to remove acids from the archival notebooks and letters there. He didn’t mention anything about historical research. Zilberstein has a salesman’s ear. “Gleb, out of twenty inventions he would make, he would choose the one you want to buy,” a former colleague told me. The library’s director at the time was a physicist, and he agreed to let Zilberstein try.

Zilberstein asked to work on the papers of Mikhail Bulgakov, the modernist playwright and novelist. Zilberstein reveres Bulgakov—a 1988 TV movie of Bulgakov’s “Heart of a Dog” is his favorite film—and he was upset by what he found. The librarians seemed powerless to stop the papers from falling apart. “It was horrible,” he said. In the next two years, Zilberstein made several trips to the manuscript department, testing different prototypes of his plastics on Bulgakov’s notebooks and drafts.

Zilberstein has a powerful bearing. He has brown ringlets down to his shoulders, and he dresses more like a session musician or a Mediterranean night-club owner than like a “higher-technology person,” which is how he describes himself. When he explained how he got permission to experiment on some of the most valuable artifacts in modern Russian literature, he sometimes gave the impression that their custodians did not fully understand what he was doing. “I always have chemistry between me and the library people,” Zilberstein told me at one point. But, unlike other scientists who have been involved in proteomic studies, Zilberstein doesn’t view most conservators as inherently risk averse. Instead, he sees them—for the most part—as isolated, underfunded, and eager to learn more about the objects in their care. “They like if you give some crazy proposal,” he told me. “Each librarian likes some crazy things.”

The charged plastics removed acidic residues from Bulgakov’s papers. But other chemicals turned up as well. As a young man, Bulgakov practiced medicine. In 1916, he was posted to an isolated hospital near Smolensk, where he became addicted to morphine. Toward the end of his life, when he was finishing “The Master and Margarita,” the bewitching, hallucinatory novel for which he is best known, Bulgakov suffered from nephrosclerosis, a painful kidney disease. Bulgakov redrafted the novel many times, and Zilberstein decided to test the writer’s notebooks and typewritten pages for signs of illness or medication.

Zilberstein sampled ten pages of Bulgakov’s notes and found morphine on every one. The heaviest opiate traces were on an outline for “The Master and Margarita” from 1937 or 1938, which was on cheap, square notepaper and included drawings of blue-and-red crescent moons and an arrow pointing to the phrase “The Witches’ Sabbath.” Zilberstein felt as if he were using a magnifying glass to find hidden information in the novel. With the help of a former classmate, Zilberstein matched the drug traces to samples of prewar Moscow morphine from the archive of the city’s police department.

He sent the results to Milan. Zilberstein hadn’t told Righetti much about his work in Moscow during the previous two years. “I tried to make a gift,” he said. He and Righetti submitted the Bulgakov findings to the Journal of Proteomics in the summer of 2015. One reviewer criticized Zilberstein’s method. In order to collect the morphine residues, he had covered the manuscript pages with plastic beads. The reviewer pointed out that beads could be left behind in the documents. Zilberstein tweaked his technique, grinding up the beads and embedding them in small pieces of ethylene-vinyl-acetate film.

In the fall, Zilberstein returned to Moscow with the new EVA films and repeated the tests. This time, he also picked up twenty-nine human proteins, mostly from sweat and saliva, including three biomarkers of the renal disease that killed Bulgakov, in March, 1940. Seventy-five years after his death, Bulgakov’s molecules were all over his papers, and Zilberstein had found them, while leaving the documents intact. “This was the opening of the Ali Baba cavern,” Righetti told me.

In early 2017, Righetti set out to extract bubonic plague from the state archives in Milan. He had long been entranced by Alessandro Manzoni’s nineteenth-century novel “The Betrothed,” with its description of the epidemic that hit the city in 1630. After the success with the Bulgakov papers, Righetti had begun to discreetly approach collections in Milan that had documents from the period of the plague, to see if they might hold traces of Yersinia pestis, the bacterium that had caused the disease. Eventually, Righetti learned that he could simply examine the city’s death records.

Unlike the Marco Polo Bible or Bulgakov’s notes, the paper in the Milan archives was made from cotton and was in excellent condition. Righetti, who had retired from his official university duties, spent weeks poring over the columns of the dead. Half the city’s population succumbed during the plague. “I selected the dirtiest pages,” Righetti said. One evening, he returned to his apartment and found red spots on his legs. “I said to my wife, ‘Gee, I took the pestis,’ ” he recalled. Righetti’s wife, Adriana, who is also a biochemist, laughed at him. “She was right, thanks to God,” Righetti said.

Zilberstein flew in from Israel to help with the analysis. He and Righetti placed the EVA films in the bottom right-hand corners of the pages, where they had been most frequently handled. One of Righetti’s former colleagues, a chemist named Alfonsina d’Amato, ran the samples last March. “The harvest was incredible,” Righetti said. They extracted more than six hundred proteins from the plague records, including seventeen from the family of Yersinia pestis. Along with traces of the plague, there were rat and mouse proteins, hints of goat milk and of anthrax bacteria, and smatterings of tobacco, chickpea, rice, carrots, and maize, indicating the diet of the clerks who chronicled the disaster. Taken individually, none of the proteins found on the records was surprising. (The bacterium that causes anthrax is stable and naturally occurring.) But together they conjured an infested city, where vermin ran over the freshly written names of the dead. “We repeated the experiments over and over again to make sure that this was real,” Righetti said.

Righetti and Zilberstein published a paper on the plague results, and they were featured on Italian TV. Their method of protein extraction captured attention, too. “I basically stand in awe of the concepts that he has been developing,” Collins, the Cambridge professor, said of Righetti. Collins is an archeologist who started out studying the proteins of fossilized shellfish, in the eighties. “For the first few decades of my career, it was a pretty miserable process,” he said. But the advent of proteomics and mass spectrometry has transformed his work. “We are simply riding on the back of this incredible technology,” he said. “Righetti has been a leader in that, and we are just following.” Collins, too, uses a nondestructive technique to take samples from historical documents, but his is much simpler: it relies on capturing the proteins from rubbings that conservators routinely make with erasers. Since 2011, Collins has used the rubbings to gather biological information about medieval European cattle, sheep, and goats. He calls his work “bio-codicology”—an updated form of the traditional study of physical manuscripts.

Collins cautioned that historical proteomic techniques are still in their infancy. “We still need to learn what these things mean,” he said. But when you realize that the surface of any old object might be bearing newly discernible biological information—that you are holding a manuscript and you are also holding the stories that the manuscript is carrying—it makes you look again at the world’s libraries and archives, and wonder what secrets they contain. In 2015, researchers at the Folger Shakespeare Library, in Washington, D.C., swabbed the gutter of a Bible from 1637 and found DNA belonging to at least one Northern European, who had acne. The library did not publicize the experiment, which it code-named Project Dustbunny, partly because it took a moment to digest the implications. “It became really clear to us that, in addition to having a great research library for humanists, we have a bio-archive,” Michael Witmore, the library’s director, told me. The Folger holds a property deed that Shakespeare kept with his personal papers. “It is the shiver of proximity,” Witmore said. “The sense that a living person or a community is nearby.”

In May, Zilberstein invited me to St. Petersburg, where he was going to analyze the notebooks of Johannes Kepler, the seventeenth-century astronomer. Zilberstein had become fascinated by Kepler after completing the plague study. One of the reasons for the outbreak in Milan was the invasion of northern Italy by troops from the Holy Roman Empire, who devastated the countryside and brought germs.

During the year of the plague, Kepler was working as a mathematician for General Albrecht von Wallenstein, who was in charge of the Imperial Army. Kepler died that November, in Regensburg, and Zilberstein wondered if there might be a connection. Earlier this year, Zilberstein tracked down Peter Michael Schenkel, who used to work for the Kepler Commission, which since 1934 has edited the astronomer’s papers. Schenkel had indexed all twelve thousand pages of Kepler’s surviving work. Zilberstein called him at home. “He asked me whether Kepler was ever in Milan,” Schenkel told me, laughing. “I don’t know how he found my address.”

Zilberstein picked me up from my hotel in St. Petersburg. It was a warm, breezy morning on the Baltic. He wore stone-washed jeans, a pale shirt with a pattern of small purple flowers, and a denim jacket with white patches on the elbows. He had brought along his son, Roman, who is in his early twenties and writes the software for Zilberstein’s inventions. Alongside his protein work, Zilberstein makes a range of portable sensors, which gauge levels of pollution, glucose, or hydration, and are compatible with smartphones. In 2012, in order to both test the technology and generate publicity, he and Righetti took formaldehyde readings next to Damien Hirst vitrines at the Tate Modern, in London. The scientists claimed that the artist’s sculptures were emitting formaldehyde at dangerous levels, and later published their findings in a scientific journal.

Hirst threatened to sue. Righetti agreed that some of the calculations were wrong, and retracted the paper. “We said, ‘What the hell.’ And gave up,” Righetti told me. “I am a poor pensioner.” Zilberstein refused to sign the retraction. For the Kepler study, he had brought a new mercury sensor of his own design, to see if he could pick up any traces on the manuscripts. “Kepler for us is not Damien Hirst,” Zilberstein said. “It is more.” In the hotel, Roman showed me a black smartwatch he was wearing, which connected to the sensor and displayed the readings. Iridescent yellow letters spelled out “Hg”—the chemical symbol of mercury—and “VOC,” for “volatile organic compounds.”

Kepler is an enigma in the history of science. He was born near Stuttgart in 1571 and lived in an age of conflict and acute religious paranoia. Fifty years after his death, his laws of planetary motion helped to bring about Newton’s scientific revolution, but he was fervently devoted to uncovering the designs of God. In 1620, he had to take over the legal defense of his mother, who was on trial for witchcraft. Kepler’s writings are a swirl of geometry and science fiction, astrology and breathtaking reason. He figured out that the planets in the solar system move in elliptical orbits; he also believed that the Earth sweated and farted just like we do. Between 1601 and 1612, he was the imperial mathematician at the court of Emperor Rudolf II, in Prague. Kepler was a slight man with poor eyesight, and many of his conclusions were based on the observations of his predecessor, the brilliant Danish astronomer Tycho Brahe. But the imaginative leaps were all Kepler’s. To prove that the Earth does not move at a uniform rate around the sun—it moves more slowly when it is farther away—he measured its orbit as if he were standing “in a watchtower” on the surface of Mars. “An idea of pure genius,” Einstein said.

Catherine the Great, the Empress of Russia, bought Kepler’s papers in 1773 and brought them to St. Petersburg. Since 1938, they have been kept in the archives of the Russian Academy of Sciences, which are situated in a quiet courtyard behind the city’s zoological museum. There was a red tractor and a cottonwood tree in full bloom. The archives were behind a dull-brown metal door. “Very authentic,” Zilberstein said, nodding.

Inside, a librarian brought out a volume of Kepler’s papers, bound in white leather. Zilberstein pulled on a pair of blue latex gloves. The reading room was quiet and crowded with other researchers. Cottonwood fluff floated outside the open windows. He put the mercury sensor, which looked like a thinner version of a needle used for pumping up a football, on the desk. After talking to Schenkel, Zilberstein had decided to test a paper that Kepler based loosely on the theories of the ancient Greek mathematician Hipparchus. Kepler worked on the text, on and off, for twenty-five years, and it remained unfinished at the time of his death. I sat next to Zilberstein as he turned the long, yellowing pages, which were dense with Kepler’s handwriting, tables of figures, crossings-out, and slender, geometric diagrams representing the Earth, the moon, and the sun. “The problems are very beautiful,” the astronomer wrote, of his Hipparchus study, in 1619. “The work itself impassable.”

The EVA films were a dark, speckled green. Zilberstein had brought two sets: one for removing proteins and a new prototype, which contained chelating agents, a type of compound that can extract heavy metals. In 2010, Brahe’s skeleton was exhumed in Prague, and remains of gold, silver, and arsenic were found in his beard, bones, and hair. Brahe was an ebullient figure—he had a brass nose from a duelling incident—and a keen sponsor of alchemy, a common pursuit at princely courts at the turn of the seventeenth century. Zilberstein was curious to see if similar metals would turn up in Kepler’s papers. He spent an hour going through the Hipparchus pages, looking for what he called suspicious places—marks of spittle or discoloration—on which to put the films.

Thirty-two pages in, next to the words “solis longitudinis,” Zilberstein found what looked like a set of Kepler’s fingerprints, in black ink, spreading across the right-hand margin. Carefully, he put seventeen films on the manuscript, including a control on a blank page at the back of the volume. He waved the mercury sensor over the desk from time to time. The rules of the archive prohibited photography. After a while, I noticed that Roman, who was sitting next to Zilberstein, had his iPhone casually angled toward his father. When Zilberstein turned a page that he found interesting, he coughed lightly, and Roman took a picture.

We stood in the stairwell for a while, waiting for the films to work. Roman showed me some mercury readings, which had oscillated wildly, on his watch. Zilberstein was concerned about the state of the manuscript, which smelled slightly of mint, a sign that it had been treated with thymol, an antifungal chemical. “I’m not so happy with this paper,” he said. But he was relieved that the Hipparchus manuscript seemed to have been relatively undisturbed. According to the slip at the front of the volume, only sixteen people had requested the book since 1972. After an hour, Zilberstein returned to his desk and took out the films. Then he filled out the slip: “21/05/2018. Proteomic analysis.”

Afterward, we walked along the waterfront toward the Peter and Paul Fortress and a fish restaurant that Zilberstein likes, which specializes in smelt, a delicacy of the city. Over lunch, he explained that, when he was growing up, the Soviet education system had observed a strict divide between science and the humanities. “It was an idea of complete separation,” Zilberstein said. “But now we try to break this barrier.” He sees the proteomic analysis of old books and cultural objects as a way for libraries and museums to reimagine their collections—and to animate the past—in an era of mass distraction and digitized content. “How to bring people back?” Zilberstein said. “Maybe it will be interesting to look at already existing cultural objects or literature from another angle.”

I was taking notes and eating smelt at the same time. Zilberstein talked about the papers and the historical figures and objects he longed to explore: Nietzsche, Mozart’s Requiem, Orwell, the Brontë sisters, the Dead Sea scrolls. Occasionally, a piece of fish would fall onto the pages of my notebook, and I wondered whether it would be preserved and analyzed in centuries to come.

The following day, Zilberstein had a meeting at the Hermitage Museum. The state rooms were mobbed with tourists, devices aloft. In an office upstairs, Zilberstein discussed proteomics with two scientists from the museum’s conservation department. Ultimately, Righetti and Zilberstein hope to commercialize their technology—including the complex analysis that it requires—and make it available to collections and to researchers who don’t have access to their own mass spectrometer. (Later in the summer, Zilberstein signed a preliminary contract with the Hermitage.) He described the service that he and Righetti could offer as a historical equivalent of 23andMe, the genetic-testing company, but with “samples from already dead people.”

Others in the field have their own ideas. After Project Dustbunny, conservators at the Folger Shakespeare Library wondered how to best preserve documents for future analysis. One of the questions was whether dirt and fluff on the manuscript pages were suddenly valuable, containing troves of information about early-modern writers and the environments in which they lived. “We asked ourselves, ‘What is this field going to look like fifty years from now? What could these samples tell us?’ ” Whitmore, the director, said.

The rapid development of new techniques also inspires a measure of caution. Collins shared with me several recent proteomics papers that made spectacular claims that were later called into question. Because the analysis is so sensitive, there is always the risk that samples can be contaminated in the lab. The databases that are used to identify ancient proteins are also used by the food and drug industries, meaning that the most studied organisms—common plants and animals, or the agents of disease—are frequently suggested as matches, even in unlikely circumstances. “We often match to super-interesting things,” Collins told me. “But then you kind of begin to get nervous of what you have actually found.”

Last month, in London, I met Caroline Tokarski, a professor at the University of Bordeaux, who carried out some of the first proteomic testings of paintings, almost twenty years ago. Tokarski is working with the Metropolitan Museum of Art on a new form of analysis, which will enable chemists to ascertain how proteins age and bond with one another inside art works. She took a glass slide out of her handbag which looked like it had a mote of dust on it. In fact, it was a speck from the lower-right quarter of Spinello Aretino’s “St. Mary Magdalen Holding a Crucifix,” one of the Met’s fourteenth-century religious masterpieces. “It is ten to fifteen micrograms,” Tokarski said. “It is really, really few.” But each year Tokarski gets more data from smaller samples. She has had a sample from Leonardo da Vinci’s “The Last Supper” in her laboratory for four years, but she has been afraid to touch it. “The question is: do we analyze this now, or do we still try and push the techniques?” Tokarski said. “Right now, she just sits in my office.”

None of this uncertainty is helpful in persuading conservators to hand over their artifacts. “Some of them will freak out,” Dan Kirby, a former I.B.M. engineer who spent years developing a proteomics-testing technique for Harvard’s art museums, told me. “You have to creep up on them.” Many conservators regard any form of a chemical reaction with a historic artifact, even at a molecular scale, as a form of interference. Zilberstein and Righetti’s EVA films must be ever so slightly damp—like a thumbprint—in order to work. “The term ‘nondestructive,’ you have to use it with care,” Tokarski told me. Collins quoted the graveyard scene from “Hamlet”—“Your water is a sore decayer”—to explain why some conservators might hesitate. He has not been allowed to use his eraser method at either the Bodleian Library, in Oxford, or the British Library, in London. “We have been told, ‘No one is ripping molecules out of books in my library!’ ” he said.

More broadly, it is not hard to see why proteomics might appear threatening to humanities scholars, whose authority over the interpretation of manuscripts, paintings, and old objects has long gone unchallenged. Some disciplines related to the past, such as archeology, have always had a scientific bent. Others, like history and literary criticism, have not. Although museums have had chemists on their staff since the nineteenth century, conservation science—analyzing pigments, taking X-rays—has generally played a subordinate role to traditional forms of connoisseurship.

Proteomics, with its research dollars and promise of hard data, has a disruptive quality. In St. Petersburg, I sensed that Zilberstein didn’t merely want to bring a new scientific tool to the aid of historians and literary scholars—he was interested in obtaining chemical data that could rewrite the historical record all by itself. “You know, historians and other people feed us with some stories,” he told me. “Now it is a good time to get objective information. Molecules, not people, start to talk. This is interesting.” Science has altered archeology beyond recognition since Collins entered the field, sharpening inferences and broad theories of the past with fine-grained data from the lab. “These new technologies allow us to get a level of detail that we never thought was possible,” he told me. A manuscript’s text is only part of its story. “What is history?” Collins asked. “When scientists start interacting with historical documents, when does history end and science begin?”

“There is kind of a defensive crouch in the humanities about how we relate to the sciences,” Witmore said. Nonetheless, he predicted that proteomics-driven papers will start appearing in literary and historical journals in the next five years. “Whether it is data mining or proteomics or genomics, people in the humanities have potential new friends,” he said.

In late July, I flew to Milan to learn the results of the Kepler investigation. I met Righetti at the university’s chemistry department. Since the Marco Polo Bible study, a steady stream of ancient things has come through his lab. We looked in on some colleagues who were having a tricky time with a stretch of four-thousand-year-old Egyptian papyrus. The papyrus contained a rare description of Heracleopolis, a ruined city on the Nile, but it had changed color during an experiment. A few chemists were gathered around a vacuum cupboard, where the papyrus lay under a glass bowl, trying to make the color change back.

The Kepler study had also run into problems. Either because of the treatment of the papers in St. Petersburg or because of an error preparing the samples in Milan, the first attempt at analyzing proteins in the mass spectrometer had failed. “We are still cleaning the machine after a week,” Righetti said. “There was no way we could identify anything, so it was a disaster.” He was hoping to analyze another batch soon, but vacations were starting and it wasn’t always easy to reserve time on the instruments.

There were much more intriguing results, however, from Zilberstein’s metal analysis. The chelating films had picked up traces of gold, silver, lead, and arsenic everywhere they had been placed, at between three and nine times the levels found on the control. Some of the mercury readings had been even higher. The constellation of metals recalled the findings of the Brahe exhumation, suggesting, to Zilberstein and Righetti, a connection between Kepler and alchemy. However, in contrast with Brahe, there is no record of Kepler conducting alchemy or consuming its remedies. (In the early seventeenth century, alchemy, in addition to pursuing the transmutation of metals into gold, was used for medicinal purposes.) Zilberstein and Righetti were thrilled, and confident in their findings. “Kepler was also an alchemist,” Righetti had told me in an e-mail a few days earlier. We got in his car to go and meet Zilberstein. Righetti rolled down the windows. “I worked forty-five years in science and nobody gave a damn,” he said. “Now every time we write a paper we get newspapers calling us up!”

The scientists and their wives met for lunch at a restaurant on an upper floor of Milan’s Galleria, with a view of the Duomo. Since the trip to St. Petersburg, Zilberstein had been planning a more ambitious study of Kepler’s manuscripts, which would map the concentration of metals on their surface, and also patterns in the astronomer’s calculations and handwriting. Zilberstein took out his phone and started flicking through the clandestine images from the archive. He was transfixed by the regularity of Kepler’s penmanship and wondered if it might contain coded messages. “I think people must reinvent their idea of who was Kepler,” Zilberstein said. “People must get this graphical information, this chemical information, this biochemical information. It will be much more curious than Dan Brown’s masterpieces.”

Zilberstein and Righetti were buoyant. They went onto the balcony and took photos in front of the Duomo. Their analysis of the Kepler manuscripts is the first time, however, that their work has sought to challenge, rather than add texture to, the historical record. When I asked them if there had been any initial reaction, among scholars, to their idea that Kepler might have been an alchemist, the scientists looked momentarily bashful. “Very upset,” Righetti murmured. That morning, Zilberstein had received a skeptical e-mail from Schenkel, of the Kepler Commission. “He said he did not believe it,” Zilberstein said.

I showed a draft of Righetti’s paper to Ulinka Rublack, a history professor at the University of Cambridge, who is an authority on Kepler’s life and writing. She, too, was unconvinced. Unlike Brahe, who was a wealthy aristocrat, Kepler was always hard up, and he avoided working with his hands, an unlikely combination for an alchemist. “He was the imperial mathematician. He was one of the most ambitious scientists,” Rublack said. “He would have needed a big lab and infrastructure to do it on any satisfying level.” Kepler’s writings, moreover, convey an intellectual life that was teeming enough as it was. “It really wasn’t how he saw himself, and what he was doing,” Rublack said. (Newton, by contrast, wrote extensively about alchemy.) In response to Zilberstein and Righetti’s findings, Schenkel examined everything that Kepler is known to have written about alchemy. Schenkel shared his report with me. The astronomer’s references are sparing, polite, and noncommittal. “I am no Chymicus,” Kepler wrote in 1604.

As long as the metal traces are Kepler’s, however, the possibility that he consumed alchemical remedies remains. “You know, this is the great riddle,” Schenkel admitted. “I wonder myself.” Asserting that Kepler practiced alchemy is obviously more appealing than finding evidence that captures unspoken, even banal, fragments of the culture in which he lived. But that might be where the chief value of proteomic and chemical analysis of old papers ultimately lies. “It is the irony of history that the most obvious things are the least discussed,” Patrick Boner, a visiting scholar at the Catholic University of America, who has written a book about Kepler’s astrology, said. “The way that people conceptualized time, remedies, health, even their bathing—all these kinds of things that are very routine—were very informed by things like astrology and alchemy.”

When I sent Righetti and Zilberstein’s Kepler draft to Boner, he told me he already knew their work, from their plague paper. “It’s opening a door,” he said. “The thing I appreciate about this project is how much more lies beyond any kind of written records.” Kepler once wrote, of his own search for knowledge in the movements of stars and matter and unimaginable things, rather than in the lessons of the printed word, “It is as though I had read a divine text, written into the world itself, not with letters but rather with essential objects, saying: ‘Man, stretch thy reason hither, so that thou mayest comprehend these things.’ ”

Toward the end of lunch in Milan, Zilberstein and Righetti talked about a trip they had planned to Paris, to capture Casanova’s gonorrhea. They parted at the entrance of the Galleria, and I crossed the square with Righetti. He wanted to show me the city’s museum of twentieth-century art. It was a baking-hot afternoon, and Righetti looked like another tourist, with his camera and his phone on a lanyard around his neck. On the first floor, we stood for a while, looking at the paintings of Umberto Boccioni, a Futurist whom Righetti admires. We ended up in front of a small, brilliantly colored landscape called “Port Miou,” painted by Georges Braque when he was twenty-five. The sea was purple and the rocks were orange and the trees were red. Righetti leaned in close. “I would like to investigate these paintings. They were taking cocaine and heroin for sure,” he said, and started to laugh. “One of these days, we will do it.”