Yuan xi qi qi tu shuo lu zui (Diagrams and explanations of the wonderful machines of the Far West), often abridged as Qi qi tu shuo (Illustrations and explanations of wonderful machines), was the first book produced in China to introduce Western mechanical engineering. Written in a systematic manner, it is the work of Deng Yuhan, the Chinese name of Johann Schreck (also called Johannes Terentius, 1576−1630), a German-born Jesuit, and Wang Zheng (1571–1644). The book is in three juan. Juan one contains an introduction to the nature of mechanical devices, with emphasis on such key concepts as gravity, the center of gravity, and balance. Juan two contains explanations of how particular mechanical devices work, providing information on the structure and application of each device, with attention to scales, weights, levels, pulleys, disks, slopes, and the like. Juan three is about the actual uses of mechanical devices. This copy was printed by Wu Weizhong in Jinling in the seventh year (1634) of the Chongzhen reign. At the beginning of the work are two prefaces, including the 1627 preface by Wang Zheng, entitled Yuan Xi qi qi tu shuo lu zui xu (Preface to diagrams and explanations of the wonderful machines of the Far West). It is followed by the 1634 preface by Wu Weizhong, entitled Qi qi tu hou xu (Postscript to the diagrams of the wonderful machines), and the editorial guide to the work. The engraved illustrations are interwoven with the texts. Some pages show the illustrations above and texts below. The copy was in the private collection of Zheng Zhenduo (1898−1958) before entering the National Library of China. It has several seal impressions, including “Changle Zheng Zhenduo Xidi cang ben” (Book in the collection of Zheng Zhenduo, Xidi, of Changle) and “Changle Zheng shi cang shu zhi yin” (Seal of the book collection of Zheng Zhenduo of Changle).