The evolution of architecture resembles nothing so much as the fleshing out and refinement of an organism, in William Mitchell’s condensed account. In pre-industrial times, architecture was “fundamentally skeleton and skin—a structure that protects and keeps out the weather.” The industrial era brought an increasing awareness of the mechanical physiology of buildings: “the flows of electricity and waste removal were overlaid on the skeleton.” In our own times, buildings have acquired “artificial nervous systems” superimposed on the flow networks. Mitchell embraces new architectural forms emerging from this latest digital technology, and gestures toward entire cities connected by a mesh of intelligent buildings. He sees “more interesting urban expressions beginning to develop,” among them Chicago’s Millennium Park, where the Crown Fountain displays giant digital images of city residents through whose mouths water flows. As information becomes increasingly mobile, opportunities arise in nontraditional public spaces for digital access, and work, creativity and social clusters emerge.