I love David Graeber's Debt so much, but it's hard to say why. That's partially because of how much I like it and partially because it seems to be about so much.
The idea is to look at human history and how the idea of debt has been constructed. Graeber talks about societies where money is used only for the important things in life and the idea of being in debt for something like food makes little sense. He goes into the myth of barter ever existing the way Adam Smith and so many subsequent economists talked about it. He goes into a history of merchants through the world (not limiting himself to Christendom, which means his conception of the Middle Ages start off in China and India) and how religions incorporate their society’s struggle with the idea of all-purpose money. There’s stuff about the ages when Christ and Gautama and Mohammed were changing the world and how separating economics from religion is crazy.
It was an amazing book. I have my buddy who knows about economics reading it now so I can get a bit more informed opinion about it, but for now, I would recommend it to anyone who enjoyed/had their thoughts provoked by Guns Germs and Steel.