From the Document: "North Korea has posed one of the most persistent U.S. foreign policy challenges of the post-Cold War period. With recent advances in its nuclear and missile capabilities under leader Kim Jong-un, North Korea has become a grave security threat to the United States and its allies. Beginning in January 2018, North Korea launched a diplomatic campaign of engagement with South Korea, the United States, China, and other countries that produced an inter-Korean summit in late April. As of early May 2018, plans were underway for a summit between President Donald J. Trump and North Korean leader Kim Jong-un.' This document contains a selective list of CRS [Congressional Research Service] products covering North Korea, followed by a list of CRS experts and their contact information."
CRS Report for Congress, R45056
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html