'Guanzi a Nei Ye': the earliest classical work of qigongology in ancient China

'Nei Ye' of 'Guan Zi' which was a famous work in the Warring States period of ancient China, first pointed out that Jingqi is the original source of all thing in the natural world; expounded the cardinal principle of qigongology that Jigqi in nature is the material base of living body of a human being, and health and longevity, and that persons can obtain the qi in the quiet of mind; and described the basic skill of doing qigong exercises. So 'Nei Ye' had formed a full system of qigongology, and was the earliest classical work of qigongology in ancient China.