An exhibition at the National Library of China in Beijing illustrates how books published between the 15th and 19th centuries allowed China and the West to gain insights into one another.

In most history books, the Manchu Qing Dynasty (1644-1911) Emperor Kangxi is depicted as nursing great ambitions to make his country strong and prosperous.

But under his reign (1662-1722) the empire is known for its exclusion, Sino-foreign trade and communications having been strictly curbed.

But that page of history does have another side. Anyone seeing a Manchu-language edition of Euclid's Elements at a new exhibition in the National Library of China is likely to gain a new understanding of this emperor.

Thanks to a group of European missionaries serving for the imperial court, Kangxi was exposed to Western natural sciences and technology. He was obviously a keen student of Elements, using red ink to highlight certain sections.

"The emperor believed his divine power derived from heaven," Zhao Daying, a researcher at the library, says.

"He thus felt that he was given the privilege of knowing the rules of nature and of the universe. But that privilege did not extend to others; he did not disseminate what he learned to a larger circle at all."

More than 300 precious ancient books throughout Chinese history, collected from 40 public institutions and 30 individuals nationwide, are now on display in an exhibition celebrating the 110th anniversary of the National Library of China that opened on Sept 7.

Compared with other national treasures in the library that tell of the country's history in a matter-of-fact way, this exhibition comes across as truly exotic. As with Kangxi's geometry textbook, dozens of other exhibit give visitors a special insight into Sino-Western communication.

In the footsteps of the Italian Jesuit Matteo Ricci (1552-1610), European missionaries continued to come to China in the late Ming (1368-1644) and early Qing dynasties, introducing important Western books of the time to the country.

The Belgian Ferdinand Verbiest, also an astronomer, was Kangxi's first teacher of Western sciences. A collection of illustrations presenting his astronomical instruments, printed in 1674, is displayed in the exhibition in Beijing. The book in which they are contained is on loan from Liaoning Provincial Library.

The Qing rulers obviously had an insatiable thirst for knowledge, evidenced by the fact that they were willing to plow themselves headlong into original works, language barriers notwithstanding.

In the Epitome of the Almagest, printed in Venice in 1496, are remarks written in red ink, indicating that it was reviewed by an emperor. The work consists of the observations of the German scholar Johannes Regiomontanus on Almagest, by the Greek astronomer Ptolemy.

This book is particularly precious because it is one of the rare remaining books printed in Europe before the 16th century, Zhao says, of which the National Library of China possesses just five.

The library now houses about 60,000 copies of ancient books in Western languages, not counting works in Russian.

Despite that paucity - there are nearly 3 million ancient books in the library - Zhao says many of the Western books in the collection are priceless. Space for the 110th anniversary was limited, so it was extremely difficult for her and her team to decide which books should go on display, she says.

Other highlights include a Latin version of Copernicus' The Revolution of Heavenly Spheres from 1566, De humani corporis fabrica, a milestone in human autonomy, printed in Basel in 1543, aversion of Theatrum Orbis Terrarum from Antwerp from 1570 that represents the world's best mapping technique in the 16th century, and Navigations and Travels by Giovanni Battista Ramusio, an Italian collection of explorers' firsthand accounts of their travels, from 1583, those explorers including Marco Polo.

"Whenever Marco Polo is talked about, studies usually focus on the accounts of scholars who came much later," Zhao says. "However, we believe Ramusio probably saw the original manuscript of The Travels of Marco Polo in his lifetime because some records in this book are rarely mentioned in other versions.

"As we prepared for the exhibition, we were surprised at how many comments we came across. That will no doubt inspire new perspectives in studies of Marco Polo."

By accident or design, many missionaries who came to China from the late Ming to the early Qing dynasties, acted like Marco Polo in reconnecting the cultural knots between East and West that had been cut off for centuries following the wane of the ancient Silk Road.

One essential task in such cross-cultural communication would have been compiling bilingual and multilingual dictionaries, some of which are on display in the exhibition.

The difficulties that the French Sinologist Alexander de la Charme would have had to overcome as he wrote a French-Chinese-Mongolian-Manchu dictionary from 1758 to 1767 are barely imaginable.

The 17th-century Italian missionary Basilio Brollo de Gemona spent 24 years in China and com-piled a Chinese-Latin dictionary.

"Among the dictionaries Western missionaries compiled in those days, this is without doubt the best bilingual one," Zhao says. "However, one drawback is that it is extremely heavy, needing two people to carry it."

Westerners' knowledge of China also improved greatly in this multicultural interaction. As modern cartography began to make its mark, Chinese maps began to resemble those that we see today, says Weng Yingfang, a librarian in charge of Western map studies at the library.

She singles out Martino Martini's Novus Atlas Sinensis (new Chinese atlas), printed in Amsterdam in 1655.

"It's the most authoritative reference in the Western world then relating to Chinese geography. It's based on his travel all around the country."

However, in the atlas the Great Wall is located much further north than it really is, and some researchers have postulated that Martini, who lived in southern China, in fact never had any firsthand knowledge of the wall.

The exhibition depicts works related to early modern technology as well as anatomy and mathematics being introduced to China by means of Chinese-translated versions of original works of the time, and in the other direction Chinese philosophy and history were widely promoted in Europe.

For example, Confucius Sinarum Philosophus (The Chinese philosopher Confucius), printed in Paris in 1687, was the first comprehensive writing on Confucianism in Europe.

The library set up its team specializing in the cataloging of its collection of ancient books in Western languages last year. That team consists of just five people, Zhao says.

"One person can make catalogs for six or seven books a day. That really is the limit, so it's going to take years to complete the job."

Despite that heavy workload she is keen for the library to acquire many more valuable works.

"Ancient books on China will always be our focus. And It will be great if we can get more pre-16th century Western works. The study of ancient Western books in China has just taken off."

Restoration of these books can be painstaking and requires great patience.

Hou Yuran has spent the past decade in the conservation room of the library, the only restorer in the library specializing in ancient Western books.

Hou, who graduated from the University of London having studied paper conservation, opted for the library job only out of curiosity, she says, but now sees it as a vocation.

"In restoring ancient Chinese books the thing you are mainly dealing with is damaged paper, whereas with Western books it is the spines that are the most damaged, which is because of different ways of binding.

"In restoring Chinese books the emphasis is on traditional craftsmanship. When I'm fixing Western books I find it sometimes makes sense to use traditional Chinese methods rather than relying on what I learned in London."

Nevertheless, the principles of restoring Western and Chinese books are similar, she says. These include minimum intervention, ensuring the book retains its old look, and for future reference leaving a record saying where a work has been restored.

"If you compare conserving ancient books to sitting on a cold bench, for those of us who look after Western books the bench is even colder. But it's never boring. You get so caught up in it that your sole concern is turning out something of top quality."

The Western texts in the library are put on display far less frequently than their Chinese counterparts, and on those rare occasions there is great demand for Hou's expertise.

"My favorite working rhythm - just sitting there - is disrupted," she jokes. "However, the public finally get to see all the work we've been doing, and that's great."