Ken Yeang has become synonymous with the term the green skyscraper. The Malaysian-born architect has changed our perception of the high-rise, questioning every premise on which it was founded. It has long been assumed that skyscrapers, as high consumers of energy and materials, cannot be sensitive to ecological and environmental issues. Yeang's towers, by contrast, use vegetation as a crucial component of the facade and interior, acting both to remove heat and purify the air. In a wider sense, Yeang sees skyscrapers as cities in the sky, with good pedestrian linkages, public zones, a wide variety of uses, stunning vistas and a sense of place extended upwards. His philosophy has had a global impact. By the year 2025 more than 70 per cent of humankind will be city dwellers. Yeang's solutions for the skyscraper, discussed and illustrated in depth in this monograph, offer a vision of urban habitation in the 21st century.