A Canticle for Leibowitz by Walter M.Miller. I've been meaning to read this for years. I'm 28% in, by Kindle reckoning, and it's pretty good.
You Kindle users are well informed
Stumbling on Happiness by Daniel Gilbert. 20% of the way through. Let's see if I make it.
I have a hard time sticking with non-fiction. I'm on a diet from my usual sci-fi/fantasy fare.