Debt: The First 5,000 Years

by David Graeber

The moment one casts matters on a broad historical scale, though, the first thing one learns is that there’s nothing new about virtual money. Actually, this was the original form of money.

The difference between a debt and an obligation is that a debt can be precisely quantified. This requires money.

everyone is in debt to everyone else in a dozen different ways, and that most transactions take place without the use of currency.