The book presents in an understandable way, using simple diagrams and equations, the basic tools and examples of Macroeconomics, highlighting the functioning of the market for goods and services in a small and open economy, the role of money, and the determinants of unemployment and inflation. The authors aim to help students understand the overall functioning of the economic circuit, the interdependencies between the main economic variables, and the role of economic policy in improving economic performance, so that they can interpret economic phenomena and predict the consequences of economic policy. The innovation of the book lies in the extensive references made to the Greek economy with data and examples that extend up to 2000. The book is mainly aimed at students of Greek universities and the University of Cyprus who are taking the introductory course in Macroeconomic Theory and Economic Policy.