Lao Tzu (Chinese: 老子; Hanyu pinyin: Lǎozǐ; Wade-Giles: Lao Tsu or Lao Tzu) was a Chinese philosopher who wrote the book: "The Tao Te Ching" ("The Way" or "The Path") which became the foundation for the philosophy of Taoism. 
His exact date of birth is not known but he is believed to have lived during the time of the Zhou dynasty. Lao Tzu was not his true name, but a title of honor that was given to someone considered to be a wise sage; it translates as "Old Master." 
According to legend, Lao Tzu worked as custodian of archives in the Emperor's library. At the age of 80, disillusioned by the wordliness of men, he decided to leave civilization and embark on a journey into the desert, riding a water buffalo. When he arrived at the final gate of the great wall protecting the kingdom, the gatekeeper persuaded him to record the principles of his philosophy in a book (The Tao Te Ching) for posterity before he left. 
Lao Tzu believed that the way to happiness was for people to learn to live in harmony with nature. This idea is called "wu-wei", which means "doing by not doing".  His philosophy was that everything alive shares a universal life-force. The two sides to the life-force are called the Yin and Yang.
Quotes from the Tao
"A journey of a thousand miles begins with a single step". 
"Those who know do not speak, those who speak, do not know"