Xu Jun (허준, 1546–1615), courtesy name Qingyuan and pseudonym Guyan, was born in Yangcheon, Gyeonggi Province, Korea in 1546 and passed away in August 1615 at the age of 70. He was a renowned physician during the reigns of King Seonjo and Gwanghaegun of the Joseon Dynasty, as well as the author of the famous medical text *Dongyi Baojian* from the East. Although completed slightly later than Li Shizhen's *Bencao Gangmu* in China, *Dongyi Baojian* is comparable in significance. Moreover, *Dongyi Baojian* primarily focuses on medicinal materials produced in Korea, making its content more applicable than that of the Ming Dynasty's *Bencao Gangmu*. Completed in the second year of Gwanghaegun's reign (1610), this book introduced many new perspectives to address the declining state of medical knowledge in the Ming Dynasty. It not only greatly influenced the development of Korean traditional medicine but also received high acclaim after its publication in Japan and the Qing Dynasty in the 18th century. Today, the book has been translated into multiple languages and published worldwide. Xu Jun's other works include *Yeoksinbang*, *Sinsan Onbang*, *Eonhae Gujeupbang*, *Eonhae Smallpox Jipyo*, *Eonhae Taesan Jipyo*, *Maijue Jipseong*, and *Jwando Bangnon Maijue Jipseong*, among others. The term "Eonhae" refers to texts written in the Korean language (rather than classical Chinese).