Taking the ethical foundations from the seminal UN Report (1987) Our Common Future , this revised and updated second edition builds a model that emphasizes three equally important moral imperatives - satisfying human needs, ensuring social justice, and respecting environmental limits. The model presented identifies sustainability themes and assigns thresholds to them, defining the space within which sustainable development can be achieved wherein it recognises that different countries face different challenges and must follow different pathways. This revised edition has been brought up to date throughout and contains three new chapters exploring the history of the concept, including the status of the UN SDGs, competing indicators and models of sustainable development, and an overview of global and local changes in the six sustainability themes. It is divided into four parts, each contributing to a deeper understanding of what sustainable development is and what is required to achieve it, including an introduction to key arguments, theoretical foundations and competing models, new empirical knowledge discussing how different countries position themselves in relation to sustainable development, and future directions, offering perspectives on how it can be achieved locally and globally. Building on the extensive literature exploring needs, equity, justice, environmental science, ecology, and economics, this book will be essential reading for everyone interested in the future of sustainable development and in the complex environmental and social issues involved.