This volume addresses a rich variety of co-ordination issues in macroeconomics. It contains detailed studies in economic policy, monetary economics, and growth theory and uses various methodologies to address the coordination issue: from a pure theoretical to an empirical econometric approach. It is stressed that modern macroeconomics should focus on coordination issues. Imperfections of various kinds are likely to lead to coordination failures, which can lead to large welfare losses. Macroeconomists should address the causes and implications of imperfections and failures. The book is a tribute to one of the leading Dutch macroeconomists, Simon K. Kuipers. Simon Kuipers shows a major interest in the theory of capital, growth theory, monetary theory, and disequilibrium theory. The lines of thought have a common thread - each use frictions to explain the functioning of a market economy. The nature of the frictions varies from pure quantity rationing, like in the Malinvaud analysis, to imperfect substitution of various capital goods (like in the vintage models or assets (in the general monetary equilibrium models proposed by Tobin).Kuipers is not only interested in pure theoretical contributions, he also stimulates econometric work in line with the Dutch tradition initiated by Tinbergen. His applied work relates to policy analysis and policy prescriptions in many fields, ranging from monetary economics to distortions in the labour market. Kuipers can be classified as a true Keynesian, although he admires neoclassical theory for its rigour and compactness. He is an eclectic economist with an open eye for the different schools of thought in macroeconomics.