This book is a collection of writings by Yun Hyu (penname: Baekho, 1617-1680), a civil official and Neo-Confucian scholar of the mid-Joseon Dynasty. The writings were compiled and published by his sons after his death. As a scholar, Yun Hyu was active in criticizing the Zhu Xi’s interpretation of the Confucian classics and presented new methods of interpretation.