This is a printed report on Korean Letters, which comprehensively compiled articles and written opinions of researchers of the Society for the Study of the Korean Script, including Ju Si-gyeong, Yi Neung-hwa, Ji Seok-yeong, Eo Yun-jeok, and Song Gi-yong. The book, which contains the regulations of the Society, Hunminjeongeum (The Proper Sounds for the Instruction of the People), the origin of Korean scripts, and contemporary changes in Korean pronunciation, provided fundamental materials for completing a draft version of a book on the unified Korean spelling system titled Gungmun yeongu uijeongan (currently kept at the University of Tokyo, Japan). This is the first systematic research report on Korean Letters, and is significant in that it explained the Korean Letter system and the principles of Korean orthography.