1. This book is selected from the "Clinical Essential Reading Series of Traditional Chinese Medicine". This series of books has been best-selling for more than ten years, with cumulative sales of millions, and has long been at the top of the best-selling list. 2. The selected medical books are mostly highly praised by doctors and regarded as must-read classic medical books, occupying an important academic status. 3. The selected medical books are carefully selected by experts and rigorously collated to provide readers with accurate original texts. 4. This revision plans to adjust the format, binding form, and paper use. At the same time, it will correct the errors in the original book, rewrite the introduction, update and add instructions for use, etc. Zhang Xichun is a modern master of traditional Chinese medicine, and his book "Medicine in Medicine" is also regarded as a must-read book by the traditional Chinese medicine community. The original book is divided into seven issues. In order to facilitate readers' reading, the order has been adjusted in this revision, and the titles of the chapters have been drafted according to the meaning of the text, namely Medicines (fourth issue), Prescriptions (first, second, and third issues), Medical Treatise (fifth issue), Treatise on Febrile Diseases (seventh issue), and Medical Records (sixth issue).