Zhang reaches back to include concepts in use before the oracle bones (c. 1350-1100 B.C.)--what could be called a philosophical "prehistory." But the focus of the work is those concepts that gained currency in classical Chinese philosophy, especially those whose meanings are deeper and more difficult to grasp. Translated and edited by Edmund Ryden in consultation with the author, the book also includes helpful introductory commentary by Ryden for each section.