Which book is the oldest in traditional Chinese medicine?

Huangdi Neijing (simplified Chinese: 黄帝内经; traditional Chinese: 黃帝內經; pinyin: Huángdì Nèijīng), literally the Inner Canon of the Yellow Emperor or Esoteric Scripture of the Yellow Emperor, is an ancient Chinese medical text that has been treated as the fundamental doctrinal source for Chinese medicine for more than two millennia.

The work is composed of two texts—each of eighty-one chapters or treatises in a question-and-answer format between the mythical Yellow Emperor and six of his equally legendary ministers.

The earliest mention of the Huangdi Neijing was in the bibliographical chapter of the Hanshu 漢書 (or Book of Han, completed in 111 CE), next to a Huangdi Waijing 黃帝外經 (“Outer Canon of the Yellow Emperor”) that is now lost. A scholar-physician called Huangfu Mi 皇甫謐 (215-282 CE) was the first to claim that the Huangdi Neijing in 18 juan 卷 (or volumes) that was listed in the Hanshu bibliography correspo

nded with two different books that circulated in his own time: the Suwen and the Zhenjing 鍼經 (“Needling Canon”), each in 9 juan.[2] Since scholars believe that Zhenjing was one of the Lingshu’s earlier titles, they agree that the Han-dynasty Huangdi Neijing was made of two different texts that are close in content to the works we know today as the Suwen and the Lingshu.

The Yellow Emperor’s Inner Classic (Huangdi Neijing, 黃帝內經) is the most important ancient text in Chinese medicine as well as a major book of Daoist theory and lifestyle. The text is structured as a dialogue between the Yellow Emperor and one of his ministers or physicians, most commonly Qíbó (Chinese: 岐伯), but also Shàoyú (Chinese: 少俞). One possible reason for using this device was for the (anonymous) authors to avoid attribution and blame (see pages 8-14 in Unschuld for an exposition of this).

The Neijing departs from the old shamanistic beliefs that disease was caused by demonic influences. Instead the natural effects of diet, lifestyle, emotions, environment, and age are the reason diseases develop. According to the Neijing, the universe is composed of various forces and principles, such as Yin and yang, Qi and the Five Elements (or phases). These forces can be understood via rational means and man can stay in balance or return to balance and health by understanding the laws of these natural forces. Man is a microcosm that mirrors the larger macrocosm. The principles of yin and yang, the five elements, the environmental factors of wind, damp, hot and cold and so on that are part of the macrocosm equally apply to the human microcosm.