The Arms Control Association [2] has published a detailed look at nuclear and missile diplomacy with North Korea, a widely-cited, in-depth chronology going back to 1985. The chronology, now online [3], is particularly informative as policymakers scramble to assess and respond to the situation. It is critical to understand the back-and-forth history of efforts to constrain the nuclear and missile programs of the North Korean regime and reduce tensions with the Pyongyang regime.
Links
[1] https://www.ploughshares.org/file/827
[2] http://www.armscontrol.org/
[3] http://armscontrol.org/factsheets/dprkchron