The subject matter of this book is the planning and design of ecologically sustainable cities. It is concerned with the process of structuring public space in the city at a time when the global environment appears increasingly fragile. Any discussion of city planning and urban design, which does not address environmental issues, has little meaning at a time of increasing population pressures on a declining natural resource base, widespread ecological destruction, increasing pollution, ozone layer depletion and climate change. The long-term survival of the planet as a vehicle for sustained human occupation in anything other than a degraded lifestyle is in some doubt: in these circumstances any discussion of the aesthetics of city planning in a pure or abstract form unrelated to environmental concerns could be described as superficial. Architecture and its sister art, urban design, are said to consist of ‘Commodotie, Firmness and Delight’ (Wotton, 1969). One aspect of ‘Commodotie’ in any urban development is sustainability – that is, a development which is non-damaging to the environment and which contributes to the city's ability to sustain its social and economic structures. The pursuit of sustainable city structures presupposes also the development of a built environment of quality: one that ‘Delights’. Environmental quality in the city is, in part, determined by aesthetic values. This book aims to explore the problem of defining quality, the poetry of civic design, but seen against a backcloth of the current concerns about the environment and the imperative of achieving ecologically sound development.