Since the middle of the twentieth century, economists have invested great resources into using statistical evidence to relate macroeconomic theories to the real world, and many new econometric techniques have been employed. In these two volumes, a distinguished group of economic theorists, econometricians, and economic methodologists examine how evidence has been used and how it should be used to understand the real world. Volume 1 focuses on the contribution of econometric techniques to understanding the macroeconomic world. It covers the use of evidence to understand the business cycle, the operation of monetary policy, and economic growth. A further section offers assessments of the overall impact of recent econometric techniques such as cointegration and unit roots. Volume 2 focuses on the labour market and economic policy, with sections covering the IS-LM model, the labour market, new Keynesian macroeconomics, and the use of macroeconomics in official documents (in both the USA and the EU). These volumes will be valuable to advanced undergraduates, graduate students, and practitioners for their clear presentation of opposing perspectives on macroeconomics and how evidence should be used. The chapters are complemented by discussion sections revealing the perspectives of other contributors on the methodological issues raised.