Laozi was a famous philosopher in ancient China. His Taoist theory exerted an extremely important influence on the Chinese culture.
Laozi lived in the late Spring and Autumn Period more than 2,400 years ago. He and Confucius were contemporaries. Li was his surname and Er, his name. He styled himself Dan.
The Records of the Historian said he was a native of the State of Chu, in present-day eastern part of Henan Province.
Laozi served as the librarian, archivist and grand scribe at the royal court of the Eastern Zhou Dynasty. He took part in important political activities, so he accumulated profound knowledge and social experience. Later he resigned from his official post and lived in seclusion. As an onlooker, he pondered on social issues and human living status then.  Step by step Laozi built up his own philosophic doctrines.
The legend goes that when he stopped over at a Pass after his resignation, Laozi wrote the book Laozi at the request of Yin Xi, director of the pass. Because it discussed philosophical questions of "Dao" and "De", the book was also known as Dao De Jing, literally, the Classic of the Way and Its Virtue
"Dao" is the central concept of Laozi's philosophical system.
Laozi advanced "Dao", the core of classical Chinese philosophy.
In the history of Chinese philosophy, dialectical thinking emerged after the publication of The Book of Changes. But Laozi generalized the universal phenomenon of unity of opposites as the general law of things, the internal motive force and cause of the existence, development and change of things. This was another great contribution he made in the history of thinking.
Laozi worshipped nature. The ever-changing nature was an important source of his thinking. For example, water has different characteristics. First, it is soft and able to adapt itself to different circumstances. Second, it is content to stay in a low position and tolerant towards other things. Third, "the goodness of water is that it benefits the ten thousand creatures; yet it does not scramble." Laozi hoped that people would learn from the virtue of water so as to get closer and closer to Tao.
With great wisdom of life and dialectics, the theory of Laozi produced an extremely far-reaching influence on the Chinese nation and mankind. It still shines brilliantly when the new century is coming today.