Mr. Yuelin Jin started teaching logic in Tsing-Hua University in 1926. Until he died in 1984, Mr. Yuelin Jin taught and studied logic for more than half a century, and his contribution to the development of logic in our country is ineffaceable. Publishing Logic in 1936, he was the first logician that systematically introduced logic to China and directed the development of logic in our country. During his long teaching career, he insisted upon the truthfulness of logic and educated a lot of experts in this field. Mr. Jin delved into logical issues like: the nature of logic, the relation between the logical system and logic, the three principles of thinking, the relation between implication and inference and the eternal truth fullness of induction; then he delivered his thought-provoking insights. Mr. Jin also applied the method of logical analysis to philosophical studies and wrote two highly academic books, Epistemology and On Tao, pioneering a whole new way of philosophical studies.