One of the greatest and most revered philosophers of antiquity, Lao Tzu is at the same time one of the most mysterious and controversial figures in the history of mankind. He is known all over the world, but almost nothing is known about him, even his real name. His contemporaries called him Lao Tzu, which can be translated as the Wise Old Man, the Old Teacher, and even as the Gray Child. The harmony of the world is the harmony of opposites that produce each other and depend on each other. Black cannot exist without white, high without low, good without evil, Yin without yang. Therefore, says Lao-tzu, the best action is action by inaction. By refusing to try to change something, a person ceases to interfere with the natural course of things, and everything around itself comes into harmony. This is the path of guidance.