The sayings of Lao Tzu and the books of Chuang Tzu and Lieh Tzu are usually regarded as the earlier classics of Taoism. The authenticity of The book of Lieh Tzu is much questioned. It is only in the Chuang-tzu that we have a well-developed philosophy; and a great part of that book, especially the ‘inner chapters,’ is usually considered genuine. Chuang Tzu’s philosophy represents the main current of the Taoistic teaching.