One of the great lessons of the 20th century was the power of the price mechanism as a way of organising economic activity. In the contest between central planning and market-based economics, the latter won a crushing victory.

Exactly why that was – how the magic of the market actually works – is an intriguing tale. But that can wait. Let’s stipulate that when we can use prices to allocate resources, we should. But it’s not always possible, or even desirable to do so.