Compendium of Materia Medica is a 52-volume book on materia medica, which was written by Li Shizhen from the 31st year of Jiajing in Ming Dynasty (1552) to the 6th year of Wanli (1578), and has gone through three drafts. This book is written in the style of "following the outline", so it is named "Outline". The preface (volume 1, 2) is equivalent to the general introduction, describing the compendium of materia medica and the theory of medicinal properties.