Italian-born Roman Catholic priest, member of the Society of Jesus, scholar, author, and missionary in China. He was named a Servant of God in 2013, the first step toward canonization (sainthood).
This book is terribly difficult to find in English. I don't expect it to become tremendously popular any time soon. Luckily I have easy access to a gigantic theological library.
In this book, Matteo Ricci (still a candidate for Sainthood, but not yet) lays out his arguments for why 16th century Confucians in China should actually declare themselves Christians. He does so in Chinese, presenting arguments based on Confucianism as if Confucianism were just a slightly-misguided version of the same "True" Christian faith.
Let's give Ricci some serious points here for what he did: Learn Chinese. Write first dictionary from Western Language to Chinese. Study Confucian Scholarship. Write very long treatise in this foreign language that no one else in his Church speaks, trying to convince Confucians that the "true" path of their beliefs should actually lead them to become Catholics. That is, adapting his faith to match the local customs and history. All of these ideas! Big! Good job!
That said, to the modern lay reader, it's quaint, but not a deep read. Lots of "my religion right, yours wrong", for fairly arbitrary reasons. He really lays out his rejections of Buddhism and Taoism, often times with very unfair characterizations of the belief systems at hand (this may have been some sort of strategy in addressing his audience.) It's fun to see some parallels and how far Ricci can "stretch" to make Confucianism and Catholicism map on to each other, but it's more amusing than really interesting.
I will give points for his section on the "Cultivation of Virtue." Why does one try to "be good"? What motivates people? Is man's natural tendency to cultivate virtue or is cultivating virtue an uphill battle? Why /*should*/ one do so? I found it to be the most interesting chapter, in some part just because it led to very interesting mental tangents related to his arguments, more than his arguments themselves.
TL;DR: This book is a big deal because of what it represented at the time, not exactly because of what it says in detail today. Context is probably fascinating to religious history scholars; quaint and hard to fully understand to the modern lay reader. Not much spiritual or philosophical insight beyond what one might learn studying either religion independently.
Matteo Ricci's account of what God is in the Catholic belief. Written as an accessible aid for Chinese christians or those interested in christianity. The book was a major milestone in the adaptation of Catholicism to Chinese culture.