In ancient times, there were many books on simple health preservation, and the book "Old and Constant Words" was recommended as a good introductory book, which was very thin but detailed. There are also Health Moon Tour, Eight Notes on Health, New Books on Saving the Dead and Helping the Elderly, Health Category Compilation, Health Life Extension Record, Family Instructions for Yan Family, and Health Articles. Short stories can be seen in Ji Kang's theory of health preservation. As for other books that nourish nature, a hundred schools of thought are discussing from different angles, and the list is endless.