ABSTRACT
The explanation of persistent, mass unemployment was the central challenge that Keynes (1936) addressed in the General Theory. The descriptive statistics in the next section clearly show that, for the industrialised world, unemployment re-emerged as a significant empirical problem during the 1970s, became particularly severe in the first half of both the 1980s and the 1990s, and is rising once again at the end of 2001. As students of labour economics we need to be aware of the time path and general composition of unemployment as background knowledge for our theoretical understanding of why the labour market does not appear to clear at anything like a full employment equilibrium.
