In December, the CIA published a an edition of Studies In Intelligence with an article titled “North Korea’s Nuclear Program: The Early Days, 1984–2002.” I disagree with some of the author’s analysis, but the piece is worth a read. For example, I don’t recall seeing this level of detail concerning N Korean HE testing, though I can’t say I’ve looked lately:

Here are the footnotes:

It’s perhaps obvious, but I feel compelled to include this observation:

In Asia, North Korean nuclear questions were not a focus of intelligence or policy concern. Rather, attention was focused on [possible nuclear proliferation by] Taiwan and South Korea.