Hong Taeyong (Korean: 홍대용; Hanja: 洪大容; 12 May 1731 – 17 November 1783), art name Tamhŏn (담헌; 湛軒; lit.

Hong was an early leader of the Profitable Usage and Benefiting the People (이용후생파; 利用厚生派; Iyong Husaengpa) school of thought.

It worked to promote the industrialization of his country and the development of trade by positively introducing Western technologies to Joseon Korea.

He wrote Catechism of Eusan mountain (의산문답; 醫山問答), which contains the concepts of Earth's rotation and the equality among species and the infinity of outer space.

After crown prince ascended the throne following the passing of the King Yeongjo, Hong was appointed to local county governor.

Hong's works, including Catechism of Ui mountain, Interpretation and Usage of Mathematics, Journal as the Mentor of Crown Prince were compiled to collection, Books of Relaxed House (담헌서; 湛軒書).