This manuscript consists of a collection of writings by Choe Han-gi (1803-1877) that are widely used as a basic material for the study of his achievements as a Silhak scholar. Although the essays in the book are arranged in a rather confusing manner, they nevertheless provide a valuable link between the great Silhak scholars including Jeong Yak-yong (1762-1836) and the Enlightenment (Gaehwa) Movement of the 1880s and 1890s.