Architect and designer William McDonough speaks about his Cradle to Cradle philosophy and design practice. This vision of the hopeful, positive, and inspiring possibilities of an environmentally and economically intelligent future by design draws inspiration from the astonishing effectiveness of natural systems. Cradle to Cradle design, as opposed to "cradle to grave", offers a new paradigm for human activity that creates a sustaining relationship with the natural world by emulating living systems that are effective, cyclical, synergetic, and regenerative. McDonough has been a leader in the sustainable development movement since its inception. He is consulting professor of civil and environmental engineering at Stanford University.