In our perpetually connected, 24/7 world, sleep is often the first thing we sacrifice. We treat it not as a biological necessity, but as a luxury we can’t quite afford, an inconvenience to be curtailed in the pursuit of productivity and entertainment. Yet, in the ancient Chinese tradition of yangsheng, or nourishing life, sleep is revered as one of the four vital pillars of health, as fundamental as a wholesome diet, appropriate exercise, and a calm mind. Without it, the entire structure of our well-being becomes unstable. As the 17th-century writer Li Liweng observed, sleep is an "infallible miracle drug, not just a cure for one illness but for a hundred."