Seong Ok YOO is the Chairman of the Board at the Institute for National Security Strategy (INSS). He joined the Republic of Korea’s National Intelligence Service (NIS) in 1986, and his main duties focused on inter-Korean talks and North Korean nuclear strategy. While at NIS, he served as the government representative to the Six-Party Talks and Director of the North Korean Psychological Warfare Division. From 2012, he served as the President of the Institute for National Security Strategy for four years, and later as the 14th President of the Gyeongnam Development Institute. Since 2020, he also serves as the President of the Research Institute for Diagnosis and Alternatives for Peace and Unification on the Korean Peninsula. Dr. Yoo holds a B.A. in English Language and Literature, and received his M.A. in Political Science and International Relations and Ph.D. on North Korean nuclear issues from Korea University in Seoul. He served as Vice President of the Korean Political Science Association, a Visiting Scholar at the Sigur Center for Asian Studies at George Washington University, and Director of the Center for Insight and Alternatives for Peace and Unification on the Korean Peninsula. He was awarded the Republic of Korea's Order of Merit in 2002 and the Order of Cheonsoo in 2010. He co-authored South Korea’s 70-Year Endeavor for Foreign Policy, National Defence, and Unification (London: Palgrave Macmillan, 2019). His recent journal contributions include “North Korea’s Unification Strategy and Aspects” in The Journal of Strategic Studies (published by Korea Research Institute for Strategy).