Recent evidence of widespread environmental degradation and global changes resulting from human activities have revived a debate about the sustainability of the progress of human welfare that began at least 200 years ago. In this renewed debate, the seriousness and causes of environmental degradation are subject to widely divergent interpretations. There are many conceivable sustainable futures; the most important differences among them are not technical but political and ideological. The practice of environmental planning is concerned with a wide variety of contexts and situations at the human-environment interface. Because land use is at the root of many of the problems of environmental degradation (e.g., habitat destruction, air pollution, water pollution), land use planning is an appropriate focus for consideration of the role of environmental planning in sustainable development. Planning as a profession, with its inherent future orientation and focus on public values, is well situated to deal with the kinds of problems raised in the discourse regarding sustainability. Examination of mainstream land use planning practices, however, reveals a reactive, reformist incrementalism that responds to environmental degradation caused by growth, but that addresses neither its causes nor its dynamics. Mainstream land use planning approaches have attempted to resolve conflicts between development and environment through spatial solutions at various scales. The need to plan for ecological sustainability is difficult to reconcile with the democratic ideal of local self-determination. Many alternative approaches to land use planning for sustainable development focus on design solutions. The requirements of sustainability are not merely technical, however. There are both emancipatory possibilities and their opposite in sustainability. Implementing sustainability offers planners a number of choices. They can act as mediators, demystifyers of technical information, exposers of hidden ideological assumptions, and advocates. They can strengthen existing authority, or work towards an enlightened self-determination at the local level. / Ph. D.