Huangdi Neijing says that "all diseases are born of qi", and the core of TCM health preservation is to nourish the heart, and regulating qi is the main part of this core. This book emphasizes that keeping in good health requires nourishing the heart first, and tells readers that "essence and spirit" are the three great medicines for keeping in good health and treating diseases. Peace of mind leads to self-harmony, harmony leads to peace, and disorder of qi leads to illness. The book not only points out that essence, qi, nourishment, blood and pulse are the material basis of the five gods, but also expounds the relationship between their physiological functions and activities in detail. It not only lists a large number of life phenomena and cases, but more importantly, it teaches readers some very simple and practical health-keeping rules, and comprehensively recuperates the five internal organs of the human body through the harmony of vigor and spirit, so as to achieve the highest state of health-keeping with full qi and blood, calmness and unity of form and spirit.