[Evolution of meridian theory].

<i>Zangxiang Jingmai Yuanliu Zeyin (Exploration of Origin and Development of Visceral Manifestation and Meridians</i>) reveals that the theory of visceral manifestation and meridians of TCM is evolved with Tiandao (way of heaven) in different periods of ancient times. In the Warring States period, the "way of heaven" referred to <i>yinyang</i> and four directions, based on which, the manifestation of four viscera was developed. During the Qin and Han dynasties, six meridians were developed on the basis of six types of <i>qi</i>. In terms of "six types of <i>qi</i> and five elements", five <i>zang</i>, six <i>fu</i> and eleven meridians were structured in TCM. Corresponding to the twelve cycles of the ecliptic and celestial sphere, twelve meridians were composed. The book displays a particular style of research with rich quotations, and provides a new way of thinking for the study of ancient TCM books.