Everybody who has studied economic theory has stumbled upon the conventional wisdom that barter was a precursor to money. It seems like we have the 18th century Scottish philosopher Adam Smith to thank for the prevailing idea that quid-pro-quo exchange systems (e.g. trading nails for potatoes) preceded economies based on currency, and that credit and debt are concepts that came only after we had invented money.

Graeber argues quite convincingly that there’s no evidence whatsoever that Smith was right. Instead, he presents a mindblowing reversal of this conventional wisdom showing that before there was money, there was debt. Going back 5000 years to the first agrarian empires, we can see from preserved records that people have used elaborate credit systems to buy and sell goods.