This book is described on purpose of revealing educational system in Koryŏ(高麗) period. The author describes this subject into five chapters - schools and installation of national Confucian academy, Kukchagam(國子監), educational reforming in early Koryŏ(高麗) period, evolution of educational system in late Koryŏ(高麗) period, country-district schools, establishment and development of Hyanggyo(鄕校) and establishment and transition of twelve assemblies, Sahak 12to(私學十二徒). Each chapter is independent research paper and has each argument. In addition, the author also considers how each educational system had been changed in the course of continuous changing history.