In the critique of political economy which became his life work Marx set out, as he put it in the Preface to the first German edition of Capital, to “lay bare the economic law of motion of modern society”. One of his conclusions was that the expansion of production under capitalism did not proceed at a smooth, steady pace, but was “a series of periods of moderate activity, prosperity, overproduction, crisis and stagnation” (Capital Vol I, Pelican, p.58), in which the long-term trend was nevertheless upwards.

The crisis which marked the end of the period of boom took the form of a financial crash—that is, a collapse of credit and a strong demand to be paid in cash. This gave rise to the illusion that the crisis was simply a monetary question whereas in fact the monetary crisis was a reflection of the real overproduction that had taken place.