Whether or not Lao Tzu was a historical figure is uncertain, but the wisdom gathered under his name in the fourth century BC is central to the understanding and practice of Taoism. One of the three great religions of China, Taoism is based upon a concept of the Tao, or Way, as the universal power through which all life flows. The Tao Te Ching offers a practical model by which both the individual and society can embody this belief, encouraging modesty and self-restraint as the true path to a harmonious and balanced existence.