Reviewers tell us that Case/Fair is one of the all-time bestselling principles of economics texts because they trust it to be clear, thorough and complete. This well-respected author team is joined for the 9th edition by a new co-author, Sharon Oster. Sharon's research and teaching experience brings new coverage of modern topics and an applied approach to economic theory, as demonstrated in the new "Economics in Practice" feature. Introduction to Economics; Concepts and Problems in Macroeconomics; The Core of Macroeconomic Theory; Further Macroeconomic Issues; The World Economy For those looking for a trusted and authoritative principles of macroeconomics text that focuses on international econmies as well as the Keynesian Cross. Case/Fair/Oster believe strongly, that a text should use the Keynesian Cross carefully and systematically, to build up to the AD/AS model. One of the great benefits of this approach, is that students of economics won't mistakenly apply what they learned about simple demand and supply to aggregate demand and supply. (A detailed summary of this approach can be found in the preface).