Here is a very interesting article in The New Yorker, tilted ‘The Invention of Money’. It describes the origin of paper money, fiat money, central banks and the fractional-reserve system.
In it, I found the following 18th century quote by John Law quite fascinating –
“Money is not the value for which goods are exchanged, but the value by which they are exchanged”.
It’s also quite interesting to note that our modern day financial system has come about by an evolutionary process of trial and error. Well worth a read.