As populations grow, where and how we live is a major concern. Very often architects address the issue of housing, and converting spaces is normally a more satisfactory solution than building from scratch. This volume examines re-purposed sites, reclaimed quarries, former landfills, unused spaces that have been recognized in the last twenty years as potential venues for the development of new social, economic and environmental assets. A selection of “recycled” projects from various parts of the world provides a map of the state of the art internationally, describing what has been achieved to date and opening a window onto possible scenarios for the future. In addition to the many images and references, a brief study illustrates the project methodologies in order to provide fundamental guidelines for planning and design.