In a recent audio podcast, Logos interviews Craig concerning how the background commentary came to be (and, more briefly, the miracles book).
https://www.youtube.com/watch?v=Yln39__aaLo
(The link here can be opened most easily after you click into this post.)
The link below should have the same interview.
https://soundcloud.com/logos-bible-software/m-ed-podcast-07-31-2014
