Today Hayek's social philosophy is considered the centrepiece of his famous and wide-ranging work, and although he is well known for his campaign against inflation and his proposal for competing currencies, Hayek's earlier work on monetary economics has largely gone unnoticed. In the following I want to show that Hayek's later monetary writings are firmly based upon foundations that were already in place in the 1920s and 1930s, so that from this perspective the evolution of Hayek's monetary thought and the differences between his and competing approaches can be better evaluated.