Zhuangzi or Chuang Tzu
The Chuang Tzu is considered one of the older books of Taoism. The book was written before 300 BC by Zhuang Zhou. The first seven chapters or the “inner chapters” are consider to be part of the original work. The remaining 26 chapters or “outer chapters” are probably written by other authors. All the chapters are dated to be written before 200 BC.