The oldest and greatest classic literature extant in China is Huang Di Nei Jing (Huangdi's Canon of Medicine), which laid out the overall picture of theoretical framework and thus marked the new stage of the development of traditional Chinese medicine. Huang Di Nei Jing (Huangdi's Canon of Medicine) was written in the form of questions and answers.  It is actually a product of various unkown authors from the Warring States Period (475-221 B.C.) to Qin (221-207 B.C.) and Han Dynasties (206 -220).  It consists of two parts: Su Wen (Plain Questions) and Ling Shu (Spiritual Pivot).  The former mainly deals with organ system, meridian system, etiology, diagnosis and treating principles; the latter, with theory of yin-yang, the five elements, points, needles and techniques etc.  The latter is also known as Zhen Jing (the Cannon of Acupuncture). The main contents of traditional Chinese medicine theory in Huang Di Nei Jing (Huangdi's Canon of Medicine) are characterized by the theory of yin-yang and the five elements, and integrated concept.  The theory of yin-yang and five elements is used to explain physiological and pathological phenomena, guiding diagnosis and treatment as well.  The opposition and unity between yin and yang is the fundamental law that governs everything in the universe.  Health is defined as the maintenance of yinyang balance while disease is the disruption of it.  Meanwhile, integrated concept is higlighted in this book, too.  The human body itself is a whole and it is related to the natural environment as a whole.  Psychological and social factors play a role in the prevention and occurrence of diseases.  Superstitious practice of medicine is opposed. This book has enjoyed a high reputation and status in traditional Chinese medicine. Prestigious practitioners of diferrent ages all think highly of it.  Parts of the book were translated into Japanese, English, German, French and other languages, the effects of which on the development of medicine cannot be neglected.       Huang Di Nei Jing (Huangdi's Canon of Medicine)