There are a a lot of things to say about this book, mostly because this book contains a lot of things. I think the best word for Debt is sprawling; it's a scholarly account of the history of debt, moralities, and capitalism that touches on a significant amount of different ideas. This book definitely is not for people looking for some light reading, but I would definitely recommend it to people who would like a fresh, at times challenging view of economics and markets in general.
The firs thing to note about this book is that David Graeber is an anthropologist. He notes at the beginning that this book will take an anthropological view of several subjects only ever viewed through the lens of economics, and that this difference is bound to cause some different views. In fact, one of my favorite things about this book was that it took a look at these subjects from a new angle. I agree with Graeber that economists/capitalists get pretty stuck in their ideas of how things can and should work, so to see someone approach economic subjects from a new side made for highly interesting reading.
For example, the first thing he talk about in this book is one of economics' great misunderstandings. Economics assumes the model that society evolved from Bartering -> Money -> Debt. Essentially, we all started from a base of bartering with each other for food, clothing, weapons, etc. and this brought about specialization. Let's say you are in a tribe and you can make better arrows faster than anyone else. Instead of making arrows and hunting you will instead specialize by just making arrows and trading those for food and clothing. Everyone in the tribe finds their niche and barters away, although the fatal flaw here is that if at some point no one needs arrows you're shit out of luck. This was how bartering lead to money: there was no longer a need to trade arrows for clothing if instead you could simply sell arrows for money and purchase clothing with money, it was a middleman between goods.
Graeber comes at this from a totally different angle, instead positing that there was never such a thing as society based on bartering, but we simply started with Debt. He mentions two types of early civilizations: Nomadic tribes (Native North Americans, East Africans) and Cities centered around farming (Mesopotamia, Egypt). Nomadic tribes did barter, however they mostly only bartered with other tribes. Within tribes, there was no system of specializing in making items and trading for other things: people simply shared resources and helped their fellow tribe members if they needed something. If you didn't have any shoes, instead of making arrows to trade for shoes, you simply asked your neighbor if she could make you a pair, which she obliged. In this way you "owed" her a favor, so in a sense these people operated on a sort of debt system (although I think this is trying to frame it too much in a modern style of debt thinking, these people were parts of tight knit communities that worked together for survival so I doubt there was much a sense of owing each other favors as opposed to simply being helpful to the tribe). Mesopotamia also functioned on debt systems. Some of the earliest forms of writing in Mesopotamia are recordings of how much individuals owed each other after making deals. Additionally, much of the area used shekels (3 oz. chunks of silver) that could potentially be redeemed for barley from the central authority, and could also be used to transact. Graeber's point is that there is no one way to classify how early people made transactions, but that the idea of a society focused around bartering is clearly a myth.
I mean, theres a ton fo stuff I could go into here. The military-coinage-slavery complex, how markets were developed to help keep standing armies, how Rome has defined much of our understanding of personal property, how the New World revamped military violence, etc. There is just a ton of stuff in here, and while I didn't totally agree with everything, I think Graeber does a great job of presenting his points of view and alternative evolutions of how things came about. the one thing that I know people are going to criticize about this book is how critical it is of capitalism. American's get pretty triggered any time any criticism of capitalism comes up and Graeber does not hold back towards the end of the book. A lot of his criticisms are hard to disagree with, I also think the system poorly distributes resources and encourages violence in the name of profit, although I disagree that it hasn't lead to great technological innovations (his argument against this is 'well maybe they would have happened anyway').
All in all, I highly recommend this book to anyone who wants their viewpoints challenged and is up for some dense reading. This book can be tough to get through at times, there's a lot of info and it holds back little. However, if you can get through it I found it a rewarding read that gave me a lot fo alternative ideas to think about.