This book consists of three long papers, accompanied by a series of short comments (by Klaus Nesser, Erling Steigum, Danny Quah, Michael Bergman, and Seppo Honkapohja) and an introduction by the editors covering the main themes of the book. It combines a systematic empirical investigation into the characteristics of business cycles with a review of general theories of the patterns and dynamics of cycles. The first paper, by John Hassler, Torsten Persson, and Paul Soderlind, investigates the patterns over time of business cycles, using data from the remarkable Swedish series dating from 1860 to the present day, and will become a standard reference in the literature on empirical investigations of business cycles. The authors find that there are strong similarities between the patterns of the business cycles of many countries. The second paper, by Peter Englund, Anders Vredin, and Anders Warne, analyses the dynamics of business cycles, and uses applied econometric analysis to identify different types of exogenous macroeconomic shocks, again using the Swedish data. The authors conclude that both permanent and transitory real shocks have lasting effects on patterns of economic growth.The third paper, by Jean-Michel Grandmont, has a different emphasis and reviews the theory of endogenous shocks. In this complex and distinguished paper he argues that agents may have self-fulfilling expectations of fluctuations in business activity.