This Chapter is a dialogue from the Yellow Emperor's Classic of Internal Medicine, specifically Chapter 25, focusing on preserving life and health. The Yellow Emperor questions Qi Bo, a renowned physician, about treating illnesses that have deeply affected the body. Qi Bo explains the principles of acupuncture, emphasizing the importance of understanding the body's harmony with nature, the interplay of yin and yang, and the precise timing of treatment. He describes five essential acupuncture practices and stresses the importance of calming the spirit before treatment. The conversation highlights the holistic approach to healing, linking the patient's inner state with the natural world.