The new classical revolution seems to have transformed macroeconomics into the theory of economic fluctuations. It is, in a sense, a return to the origins of macroeconomics as a discipline as fashioned by Hayek, Keynes and Lindahl. But the scope has shifted in the intervening five decades and more. It is this new scope - and the new tools that force its expansion - that are surveyed and analysed in this volume. Foundations of deterministic and random fluctuations, equilibrium and non-equilibrium macroeconomics of cycles; economic historical and political bases of crises; and the theoretical and descriptive statistics of time series analysis - all these provide nettings for the study of business cycles.