This essay is a reprint in book format of the lead article in an edition of the Harvard Design Magazine (Spring/Summer 2003). Both the magazine and the book sought both to present the case for environmental design in architecture - the design of buildings that reduce their environmental impact AND carry cultural meaning - and position the Harvard Graduate School of Design in relation to its American academic counterparts. The essay sets out five reasons why environmental design is of interest as well as importance not only to architectural practitioners, but also architectural academics and their students. In addition to practical, technical, economic and pedgaogic reasons, therefore, there are intellectual reasons why this practice and its evolving theory should be addressed. Environmentalism is a Modernist metanarrative post-postmodernism: its aims are universal but its means are responsive to, even dependent upon, individual conditions. As the built environment contributes 50% of all greenhouse gases, the architect has a role to play in mitigating or adapting to these increasing volatile initial conditions. The essay draws on previous work by the author, in particular her book 'Taking Shape: a new contract between architecture and nature' (Architectural Press, 2001), and is aimed primarily at those who teach architectural design, among whom there continues to be resistance to the idea of a technical practice carrying aesthetic and ethical implications.