This book is about quantitative forecast focusing on mathematical model building for positive time series data. This book aims to bridge between the sophisticated nature of statistical modelling and forecasting velocity and veracity which is the next door to public policy development. For this purpose, in this book, the authors try to put statistical tools on “dining table” without going into the details but still reveal the statistical soul. The readers will find that its content is about action to take the benefit from data or information in a simple way with desired accuracy. Furthermore, since the policy makers consider “velocity” at the highest priority and “veracity” or “forecast quality” as a never ending process, whatever the data or information they use to make a forecast high velocity in constructing a desired time series model will be the focus of the book. This book designed not only for policy makers but also for those who are working with or studying positive time series modelling. Its contents are easy to digest and no special skill in statistics is required.