Master Chang Sen Feng was an active Taoist master during the Tang Dynasty (660-780 AD). He was schooled in the Chai Tzan tradition, which he practiced, expanded and taught. His personal practice led him to explore techniques that favored the use of sexual energy as a source for internal alchemy. This text, his record of the practice, disappeared for over 700 years before it was rediscovered by Jie Yi Tze during the Ming Dynasty. Shifu Hwang is a practicing Taoist from Chuen Zen School. Currently, he lives in Texas, USA. Master Hwang has devoted his adult life to promoting Taoism and balanced health care. In 1996, he established TaiChi People Herb Co. Recently, he established Immortal Cancer Care Foundation for alternative cancer care education. Cheney Crow grew up in Washington, D.C. and graduated from Sarah Lawrence College in New York. She lived and worked in England, France and Spain for several years before completing her PhD in Linguistics, then teaching at the University of Texas at Austin. She studied Long Form Yang Style and Sword Form Tai Chi with Shifu Hwang.