Dr. Kee-Joon Lee is a professor of the Department of Orthodontics, Yonsei University College of Dentistry, Seoul, Korea. He is the current dean of the Yonsei University College of Dentistry. He received DDS and PhD degree at the Graduate school, College of Dentistry, Yonsei University. He completed the orthodontics specialty training in Yonsei University Dental Hospital. He was a visiting scholar at the Department of Biochemistry, University of Pennsylvania School of Dental Medicine in 2002-2004 and at the Division of Plastic Surgery, the Children’s Hospital of Philadelphia in 2010-2011. He was an adjunct professor at the Department of Orthodontics, University of Pennsylvania between 2016 and 2019 and at Temple University between 2010 and 2011. He has contributed many book chapters on biomechanics of miniscrew-driven orthodontics, non-extraction treatment in adults, up-to-date lingual orthodontic mechanics and surgery-first approached using TADs. He is the first who demonstrated the miniscrew-assisted rapid palatal expander (MARPE) for adults in AJO-DO, which was cited by many other authors. He has published many articles and case reports regarding the treatment of non-eruption, and total arch movement for hyperdivergent face in orthodontic journals including two cover issues in AJO-DO. His fields in research include clinical biomechanics regarding TADs application and the suture and bone responses to orthodontic stimulus. He has served as a reviewer in major orthodontic journals, including AJO-DO, Angle Orthodontists and European Journal of Orthodontics. He has been invited to many international orthodontic conferences around the world.