The article describes how researchers and planners are building mathematical models of personal and civic behavior. In 1969, playboy published a long, freewheeling interview with Marshall McLuhan in which the media theorist and sixties icon sketched a portrait of the future that was at once seductive and repellent. The interview appeared when computers were used mainly for arcane scientific and industrial number crunching number crunching. To most readers at the time, McLuhan's words must have sounded far-fetched, if not nutty. Now they seem prophetic. One of big data's keenest advocates is Alex 'Sandy' Pentland, a data scientist who, as the director of MIT's Human Dynamics Laboratory, has long used computers to study the behavior of businesses and other organizations.