The authors cautiously estimate that North Korea may have produced enough fissile material to build between 30 and 60 nuclear weapons, and that it might possibly have assembled 10 to 20. Although North Korea is thought to have the capability to develop an operationally functioning re-entry vehicle to deliver an operational nuclear warhead, there is some uncertainty about whether it has demonstrated that it has succeeded in doing so. Nonetheless, North Korea’s nuclear weapons program has made considerable progress over the years, including a wide variety of ballistic and powerful nuclear tests. Presumably, if it hasn’t happened already, it is only a matter of time before Pyongyang’s nuclear arsenal can be considered fully functioning. Read the Nuclear Notebook in the January/February 2018 issue of the digital Journal. The Nuclear Notebook is always free-access.