This book gives a comprehensive account of traditional and more recent developments in macroeconomic theory. It is written primarily for students at the intermediate level. The book differs from the customary expositions in that the authors do not discuss topic by topic but orthodoxy by orthodoxy. Thus, the main approaches, like Classical theory, Keynesian theory, theory of portfolio selection, Monetarism, Rational Expectations theory, and Neokeynesian "disequilibrium" theory are presented in historical order. Each of these approaches is substantiated and criticized in a self-contained chapter, and the authors have taken great pains to bring out the relations and differences between them. A mathematical appendix reviews those mathematical facts which are especially important for macroeconomic models and serves to make the text easy to read.