The Shang Han Lun (伤寒论 — Treatise on Cold Damage) and the Jin Gui Yao Lüe (金匮要略 — Essentials from the Golden Cabinet)
Written by Zhang Zhong-jing (张仲景, 150–219 CE) during the Eastern Han dynasty, the Shang Han Za Bing Lun (伤寒杂病论 — Treatise on Cold Damage and Miscellaneous Diseases) was subsequently lost, then reconstituted and reorganised into two works: the Shang Han Lun and the Jin Gui Yao Lüe. Together with the Huang Di Nei Jing, the Nan Jing and the Shen Nong Ben Cao Jing, they form the Four Great Classics of Chinese Medicine (中医四大经典), to which every physician throughout the history of Chinese medicine has referred.
The Shang Han Lun and the Jin Gui Yao Lüe are unquestionably the most important works of Chinese medical practice. It is these works which, through the accuracy of their diagnoses and treatments, made possible the development that Chinese medicine has undergone over the centuries.
To this day, Zhang Zhong-jing's work remains the cornerstone of mastery in diagnosis and in classical prescription (jingfang 经方), and the keystone of internal medicine. The most renowned physicians refer to it, and there is no doubt that any practitioner who prescribes the classical formulas according to Zhang Zhong-jing's methods enjoys the highest reputation — for it is invariably there that they achieve the most effective and conclusive clinical results.