After years of reflection and dedication, this book brings together the most brilliant conclusions of the great Spanish economist Ramón Tamames on the international economy and its economic cycles, international cooperation, the development of world trade, or the international monetary system of the IMF and the European Monetary Union. He distills and clarifies the world economic structure and defines the strategies and limits of sustainable economy. Tamames' thoughts on the relationship between the economy and ecology, the achievement of a development that respects the planet and the economic analysis of a world endangered by the rupture of balances, such as global warming and climate change, offer us a clarifying vision of the present and future economic challenges.