Two movements have contributed to the emergence of the idea of sustainable development. The first relates to the challenge, from the late sixties, Western policies of development in the South. The second expresses concerns about the impact of human activity on the natural environment. Both offer the same critique of the model development understood as economic growth liberal to keep its promises, economic development must go hand in hand with a concern for global social justice and a strong concern for the natural environment in which all development human takes place. It is precisely this triple constraint that expresses the concept of sustainable development and tries to coexist. After twenty years of reflection and projects, it appears that the three requirements of sustainable development can not be met equally and simultaneously. In the unified program, but idealized, substitute, in fact, more specific strategies according to the priorities given to the three objectives of sustainable development. The real debate is about the most appropriate strategies to reconcile our different intuitions about economic development, respect for our natural environment and social justice. Thus, at a time when the ambitious project of sustainable development is weakened by its fuzzy semantics but also by the multiplicity of actors, policies and plans sometimes incompatible, this book provides evidence of critical analysis of different strategies for sustainable development and aims to identify major issues of a project which, despite its imperfections and contradictions, retains all its legitimacy to be, and be thought. Contributors to this item: Christian Arnsperger Christian Coméliau, Alexandra Heering, Jean-Marie Harribey Bertrand Hespel, Stéphane Leyens, Charlotte Luyckx Xavier Thunes, Franck-Dominique Vivien and Edwin Zaccai.