To increasing numbers of people, sustainability is the key challenge of the 21st Century. In the many fields where it is a goal, persistent problems obstruct the efforts of those trying to make a difference. The task of this book is to identify the philosophical failings underlying these problems, on the basis that the ways in which we conceptualise sustainability may contribute to, or alternately undermine vital projects. Using a critical realist approach, the defining aspects of sustainability are identified in order to propose a criteria of adequacy for any project, initiative or policy. This innovative work demonstrates the positive contribution that can be made to this field by an approach based in critical realism or dialectical critical realism. This study includes: A consideration of basic theoretical questions, as well as a critical introduction linking theory and practice. Key issues drawn from a wide range of different global regions. The practical, political and ideological outcomes of the ways in which we frame and conceptualise sustainability, using real world examples. A focus on the experiences and initiatives of the movements involved. Issues addressed in this context include: climate change initiatives and policies; new economics attempts to re-frame development for sustainability; the bio-fuels and food dilemma; social policy and rising inequality; poverty increases due to environmental degradation; renewed emphasis on 'leadership' for sustainability versus democratisation; conservatism and conservation; power, knowledge and sustainability in social movements; approaches to the reform or dissolution of capitalism. This very topical book will be a valuable source of information and debate for postgraduates and professionals with an interest in sustainability, critical realism or social systems.