In 1958, when I began the study of Chinese alchemy under the tutelage of Joseph Needham at Gonville and Caius College, Cambridge, knowing that the development of alchemy in China was mainly due to the work of the Daoist alchemists, I went straight to the alchemical texts in the Daoist Canon (Zhengtong Daozang )25 and at the same time began to read the writings of contemporary scholars on the same subject. The Daoist Canon consists of well over 1,000 Daoist texts, about only 7 per cent of which touch on alchemy in various degrees.