Zhuang Zi, with the given name of Zhou, lived between 369-286BC. He was another representative of Taoist school of thought after Lao Zi, as well as an excellent litterateur and philosopher. He expatiated on the essence of Taoist thought and developed the Taoist theory in his book Zhuang Zi (also known as Nanhuajing), and made it a philosophical school with a profound influence on later generations.

Zhuang Zi was born in a poor family, lived primarily on making straw sandals, and was once a official in charge of painting work. However, he was quite learned through studying the thought of all kinds of schools. In his lifetime, Zhuang Zi was indifferent to fame and gain, which seemed to him like devils rather than angels, and had long pursued spiritual freedom. At that time, Chuwang (king of the Chu State) heard about his incredible scholarship, and tried to invite him to be an official by offering him largesse. Unexpectedly, Zhuang Zi refused completely by saying: "Get out of here and don't humiliate me! I would rather live happily like a tortoise in the pond than be limited by the king! I won't be an official in my lifetime, and I will be free for ever!"

Zhuang Zi took Tao as the universal basis, and held that Tao lies in everything,and it is the root and basis of all existence and transformation. He proposed the all-in-one idea, and believed that everything in the universe originates from the same thing, and it is an integral whole in various forms. Based on this point, he claimed that all the difference between big and small, living and dead, right and wrong, etc., is relative, and such kind of differentiation turns out to be meaningless.

Dissatisfying with the social reality and tired of the worldly life of that time, Zhuang Zi tried to escape from the worldly stipulation and to attain spiritual freedom. The saints and immortals in his mind should be absolutely free, subject to no limits, dependent on nothing; and by taking only breeze and dew, he could go anywhere in the universe. In fact, what he pursued was a kind of transcendency, a state where one wouldn't be affected by anything, no matter right or wrong, good or bad, pleasant or unpleasant, and a state where one could get free and full development. He regarded those who were after fame and gain as shortsighted sparrows and cicadas, who were incomparable to the ambitious rocs. He treated life and death simply as a kind of natural transformation like seasonal change. In his eyes, nothing was worthy of celebrating or grieving; or rather, death was a way to escape from the worldly tortures.

With vast wisdom in it, Zhuang Zi's thought has a profound influence on later generations. His all-in-one theory marks a big advance in people's efforts of trying to know the world. He argued that judgment can't be made subjectively, because while the world is infinite, the cognitive ability of an individual is finite; it is impossible for human being to know completely about the world. In this way, he raised two basic questions in terms of epistemology. Although his answer is not necessarily right, or rather, ex parte or wrong, the questions themselves were of great significance. Despite the fact that Zhuang Zi's philosophy tends to be pessimistic, it indeed plays a part in reducing people's agony by providing a psychological balance when they are in predicament. In this sense, it is a makeup for the philosophy of being active and achieving.

The book Zhuang Zi, as an important part of Taoist works, consists of 33 articles, including Neipian (inner section), Waipian (outer section) and Zapian (mixed section). It is generally believed that Neipian was written by Zhuang Zi himself, but other two were done by his pupils and his other followers. It uses numerous parables to explain the complicated philosophy, and is of high literary value due to its aesthetic beauty in words.