A friend of mine recently highly praised a Sci-Fi book he read, but could not recall the author/title since he read it a while back.
He did provide many details but apparently not enough for my Google Fu to identify it, thus I'm turning to the collective wisdom of this site.
The book involved a future where all the military technology was developed and built on the Moon. It evolved to the point of Gray Goo (nanotechnology) and eventually ended up on Earth and wiped out all of Earth's technological infrastructure.
An additional detail he remembered was that the protagonist suffered from some form of amnesia and could not warn people about the danger because of it.