In many areas of the world, environmental degradation in and around human settlements is undermining prospects for both socioeconomic justice and ecological sustainability. To explore the issues involved in this worldwide problem, the author focuses on a dramatic instance of conflict that grew out of the unauthorized penetration of human settelments into the Ajusco greenbelt zone, a vital part of Mexico City's ecological reserve. The Mexican government's initial response to these "irregular" human settlements was contradictory and reactive. Social unrest, ecological deterioration and violence have all been part of the continuing crisis. The heart of this book is the story of what happened when residents of Los Belvederes, a group of Ajusco settlements, fought relocation by proposing that Los Belvederes be transformed into Colonias Ecologica Productivas, or productive ecology settlements. Through innovative organized resistance, their grass-roots movement generated environmental and social action that eventually won crucial state support. The author draws upon urban and regional planning theory and practice to examine biophysical as well as ethical and social sides of the story, and uses the Mexican experience to identify planning strategies to link economy, ecology and community in sustainable development.