This Chapter is an excerpt from The Yellow Emperor's Classic of Internal Medicine, specifically Chapter 10, "The Spiritual Pivot – The Meridians." It details the pathways, functions, and diagnostic implications of the twelve primary meridians in Traditional Chinese Medicine, explaining their role in health and disease. The excerpt further explores fifteen collateral meridians, their pathways, and clinical significance, providing guidance on diagnosis and treatment based on pulse analysis and visible signs. Finally, it discusses the consequences of qi cessation in the Yin meridians.