Why has unemployment fallen in some countries and not in others? This classic book is now re-issued with an updated introduction, which shows how well the analysis explains recent developments. The book is both a textbook and an original monograph in which the authors set out their analytic framework which has now become standard in some countries. The book both explains unemployment and shows how it can be reduced. It contains a long overview chapter which is accessible to any non-specialist with an elementary knowledge of economics.