Translated by Eva Wong. 5.5"x 8.5", 136 pages, paperback, with a commentary by Shui-Ching Tzu. Written between the 2nd and 5th centuries, the book is attributed to T'ai Shang Lao-chun, the legendary figure widely known as Lao-tzu. A principal part of the Taoist canon for many centuries. Accompanying commentary, written in the 19th century by Shui ching Tzu, explains the alchemical symbolism of the text.