Paying for the stuff you want with currency is way easier than relying on chairs you made or chickens you raised.
When deciding whether others should make trades, children may consider who likes what.
A cashless society depends on three things, all of which have failed in recent weeks as a result of natural disasters and security breaches.
Currency first hit the scene thousands of years ago. An anthropologist explains the early origins and uses of money – and how archaeological finds fill in our picture of the past.