Xu Guangqi was one of the first promoters of Western science in China, worked together with the Jesuit Matteo Ricci on translations of Western science, was one of the first Chinese converts, a high-ranking statesman, organizer of a major calendar reform, introduced Western weapons into the Chinese army, etc. etc. The current volume is a composite profile of this complex figure that is solidly anchored in Chinese (and Western) primary sources. A major achievement.