would exchange their goods and services for bassoon performances. In a money-based economy, I can sell my services as a bassoon player in an orchestra to those who are willing to pay for orchestra concerts with money. Then, I can take the money I earn and pay for a variety of goods and services. Economists say that the invention of money belongs in the same category as the great inventions of ancient times, such as the wheel and the inclined plane, but how did money develop? Early forms of money were often commodity money-money that had value because it was made of a substance that had value. Examples of commodity money are gold and silver coins. Gold coins were valuable because they could be used in exchange for other goods or services, but also because the gold itself was valued and had other uses. Commodity money gave way to the next stage-representative money. Representative money is a certificate or token that can be exchanged for the underlying commodity. For example, instead of carrying the gold commodity money with you, the gold might have been kept in a bank vault and you might carry a paper certificate that represents-or was "backed"-by the gold in the vault. It was understood that the certificate could be redeemed for gold at any time. Also, the certificate was easier and safer to carry than the actual gold. Over time people grew to trust the paper certificates as much as the gold. Representative money led to the use of fiat money-the type used in modern economie