"Guangdan tzu" or "Book of Guandanyu" is a treatise on ancient Chinese philosophy, which was compiled by Liu An in the 2nd century BC. The book reflects various aspects of philosophy, politics, military strategy and cosmology. Liu An expresses his own views on government, power, justice and social relations. "The Book of Guandanyu" is considered one of the most important works of ancient Chinese literature, which influenced many other philosophical works of that time.