This book, of which we present an preliminary offprint version in English, is the result of a collective analysis undertaken at the invitation of the Economic Commission for Latin America and the Caribbean (ECLAC) as part of the discussions supporting preparations for the thirty-eighth session of the Commission. With the collaboration of Nicolo Gligo, it was possible to bring together a group of pioneers in the analysis of sustainable development in Latin America and the Caribbean whose thinking has been informing this field of the social and scientific disciplines since the 1970s. Their different contributions are integrated into the 12 chapters of this document, which address the great issues being debated in the region and the world in relation to development and the environment. In the authors’ opinion, humanity is at a crossroads. They argue that increasing harm has been done to the planet’s biosphere, aggravated by climate change, in the context of an international economic order that is unbalanced, unfair and uninclusive. They contend that structural change is needed to bring about higher-quality development, a cultural and paradigm shift that creates the conditions for better quality of life with real concern for environmental sustainability. Their reflections highlight the urgent need to improve development metrics, currently dominated by the distorting yardstick of GDP, and address the problem of the predominance of implicit environmental policies over explicit ones. High strategic priority is given to land-use planning policies and instruments for determining degrees of suitability and vulnerability. Stress is laid on the need to move towards implementation of multinational agreements governing research into and sustainable management of land and ecosystems or geographical spaces shared between two or more countries, particularly where significant processes of change are occurring.