Dr. Lee Sangtae studied in the Department of History at Yonsei University and received his doctoral degree at Dongguk University. He worked at the National Institute of Korean History as Chief of the Office of Research on Historical Material and was an exchange professor at the University of Tokyo, Japan. Currently, Dr. Lee is the chair of the Korean Territory Society and conducts research on the dominium of Korean territory and its origin based on early regional maps and historical materials of all sources.