余凯

Yu Kai: public information about his life, native place, and dates of birth and death is limited, so his personal history cannot yet be described in detail. What can be confirmed is that three medical works are extant under his name: Gezhi Yulun, Danxi Xiansheng Jinkui Gouxuan, and Handan Yigao. Their contents concern traditional Chinese medical theory and clinical diagnosis and treatment, and they are commonly classified under medicine. Judging from the surviving works, the writing centers on the analysis of medical principles, the treatment of diseases and syndromes, and the use of prescriptions and drugs, showing the formal characteristics of traditional physicians' writings and stressing the combination of theory and practice. Because biographical materials are scarce, his scholarly origins and life still await further investigation; readers may consult the three works above to gain a basic sense of his medical writings and their documentary value.