This essay traces the progressive development of the Ecoskyscraper as a sustainable built form with examples drawn from the work of TR Hamzah Yeang In Kuala Lumpur and Llewelyn Davies Yeang in London. In 1976 Yeang set up practice with Tengku Robert Hamzah as T. R. Hamzah & Yeang and by 1986 he had completed three skyscrapers in the Malaysian capital. He also built a residence – the Roof Roof House - on the outskirts of Kuala Lumpur that was a test bed for the principles he would apply to high-rise towers. Orientation, response to sunpath and wind cone, sun shading, a double roof, adjustable parts that can be manipulated to achieve cooling by the ‘venturi’ effect, evaporative cooling, the idea of the wall as an ‘environmental filter’, and natural ventilation were incorporated. All this early inventiveness finds its way into later ecoskyscrapers.