(This is a slightly expanded version of a book review on Amazon.com)
Matteo Ricci's and Nicolas Trigault's "De Christiana expeditione apud Sinas", translated by Gallagher as "China in the Sixteenth Century", is, arguably, one of the most important books of the 17th century. (Look up that title on Wikipedia: it was me who wrote the article there). A fruit of Matteo Ricci's pioneering experience as a Jesuit missionary in China (1582-1610) it both provided Europe with its best "standard reference" on China for a the next several decades, and articulated Ricci's [[ASIN:0824812190 "accommodationist"]] strategy, which Jesuits were to follow for the next century in their attempts to make Christianity acceptable to the Chinese literati, and Chinese Confucian world view, to Europe's ecclesiastical and intellectual elites.
Matteo Ricci was not the first Catholic missionary to work in China, and not even the first one to write a book about the country. (The Portuguese Dominican friar Gaspar da Cruz, who spent a few months in Canton in 1556, and published his book in 1569, may be the one to claim the honor, if we ignore the Papal envoys who had been active in the Mongol-dominated China ca. 1300). However, what he (and his lesser known older comrade, Michele Ruggieri) did was cardinally different from what the previous generation of missionaries did. Da Cruz, or the Spaniard Martin de Rada (an Augustinian who entered Fujian from the Philippines for a few months in 1575) were utterly dependent on their interpreters, and were not all that "nuanced" about the "pagan" rites and beliefs to be condemned and exterminated. No wonder that they did not get all that far in their abortive attempts to get established in the Ming China.
In contrast, Ruggieri and Ricci, in the best Jesuit tradition, painstakingly worked on learning the spoken and written language of the country and trying to figure out what beliefs and principles guided the people of this land in their actions. All the same time, the two Jesuits plotted how they could get themselves closer to the Ming Empire's centers of power; much of the book thus is the story of their progress (taking almost two decades) from the Portuguese base in Macao to inland Guangdong's Zhaoqing and Shaoguan to more central Nanchang to the empire's "backup capital" Nanjing and, finally, to the Emperor's court in Beijing.
As a result of this enormous effort, Ricci was able to create an encyclopedic book that represented a much higher level of understanding of China than did Europe's previous "standard reference", [[ASIN:1108008194 History of the Great and Mighty Kingdome of China]] (which was written by a Spanish-Mexican Augustinian who had been appointed by the Spanish court as its envoy to China, but, alas, never got beyond Mexico). More importantly, he armed the Jesuits with a "modus operandi" that viewed Confucianism as a generally "positive" a-religious ideology, which could be used as an ally against the competing religious faiths (Buddhism and Taoism). While a modern academic study such as David E. Mungello's [[ASIN:0824812190 "Curious Land"]] may be a better way to learn about the Jesuits' approach (and the opposition to it from some of Europe's Catholic hierarchy), nothing replaces reading Ricci's original work for the sheer feeling of amazement at what Ricci and his colleagues did trying to understand the very different civilization from what they had left behind in Europe.
Well, how *can* you read Ricci's original work? His original "journals" were, naturally enough, in Italian, and not even published until the 20th century. (The work, "Fonti ricciane", with comments by Pasquale d'Elia, is not even on Amazon; see the Wikipedia article for the bibliographic information). Ricci's younger colleague, Nicolas Trigault, posthumously edited his work and turned it into Latin, and had it published in 1615; it quickly became a Pan-European bestseller, translated into Europe's most major languages; that all can be found on Google Books and/or in archive.org. The most recent English translation is apparently by the American Jesuit Louis J. Gallagher's, first published as "The China That Was" in 1942, and then (with a Chinese-words index based on d'Elia) in 1953, as "China in the Sixteenth Century: The Journals of Matthew Ricci: 1583-1610".
So the second edition must have been timed for the 400th anniversary of Ricci's birth; what surprises me is that such an important book has not been reprinted, say, in 2002 (for Ricci's 450th anniversary), or in 2010 (for the 400th anniversary of his death). But here we are: one of the most important documents of the Christian missionary history - if you want a complete English translation - is only available as an out-of-print book. Fortunately, most university libraries still would have a copy...