Forecasting has long been a core activity involving most if not all organizations. However, it is only relatively recently that it has become an area of intensive research. The earliest research was based in the core quantitative disciplines of statistics and econometrics. However, prior to 1981 there were relatively few articles whose primary focus was forecasting but with the founding of, first the Journal of Forecasting and then, in 1985, the International Journal of Forecasting, the field rapidly developed its own methodological perspectives. At its heart forecasting is concerned with evaluating alternative approaches to particular forecasting problems. Parts One and Two cover the core methodologies of forecasting. Part Three examines the evaluation of different forecasting methods and how to choose between them. Part Four includes studies that are specific to particular problem areas.