This article will review some problems with taking the notion of sustainable development, as a policy, as the touchstone of environmental education and will explore some central strands to understanding sustainability as a frame of mind. It will be argued that at the heart of this interpretation of sustainability lies the notion of a right relationship with nature which both conditions our attitudes towards the environment and our sense of our own identity. The contribution of certain influential eco-centric accounts to the idea of sustainability is critically evaluated and a sense of sustainability is developed which is neither anthropocentric nor eco-centric. It is argued that the essence of sustainability, so conceived, is intrinsic to authentic human consciousness and some of the metaphysical issues which it raises for education and modern Western society are indicated. [Reprinted from "Environmental Education Research" (2002) 8(1), pp. 9-20.]