Modern industrial society can only run on money. The Russians found that out. Not even Communism can run a modern industrial system without money. A system repasing on exchange of goods and services for goods and services-barter-would be hopelessly slow, cumbrous and costly. 'Money is what money does.' What it does is measure the relative costs, selling prices, and values of all economic activities one against another: just as inches, pints or ounces measure the lengths, volumes or weights of things. But whereas these ordinary measures never vary because if they did nobody could be sure of anything, money units-shillings, marks, dollars-themselves vary in extraordinary ways.