re: "Earth Abides" Most of humanity is gone. Can tech survive?
Surviving books or samples that described working technology would of course be a great help. The posts made about the fragility of electronic media, however, suggest rightly that much information may be lost..
IMHO one thing more important than specific knowledge would be the retention of the concept of the scientific method itself.
What are the chances of that? Do we require scientific priesthood?
You can be sure that less 'scientific' memes would be maintained, in surviving religions. Into which the downfall/calamity that befell civilization would be weaved.