'The amount of research activity devoted to nonlinear time series modeling has virtually exploded during the past decade. Many of the techniques just recently developed in that literature have already been included in the standard toolbox by macroeconomists and finance practitioners working in the public and private sectors. This latest volume in the International Symposia in Economic Theory and Econometrics series brings together a collection of new papers in this active and exciting area of research. The topics and methodologies are wide ranging, but each of the chapters is well motivated by a genuine, interesting economic problem. A stimulating read.' Tim Bollerslev, Duke University