Prof. Fabrizio Pregadio, one of the world's leading Daoist scholars, offers in this translation with commentary, a very readable and clearly explained version of an extremely important inner alchemy work called "Can tong qi" (Pronounced "tsan tong chi" in modern accent). In a very readable introduction (pp. 1-63) the origin and content of the present text is examined, after which the text itself is translated, pp. 69-126. The most important contribution of Pregadio's work is found in the extensive notes, pp. 130 to 244, which are easily understood by the lay person, and serve as a wonderful source of learning for upper division university and graduate seminars as well.The book concludes with tables and figures (245-260), the Chinese text (269-285), two indices (286-301), and bibliographical references (303-308). A must read! Recommended for university courses as well as the general public!