Many of the political problems of the day—climate change, industrial pollution, nanomaterials, new technologies of surveillance, and the products of molecular biology—involve complex scientific and technological issues that can provoke sharp divisions in public opinion. Often environmentalists and other advocates of change call for policies that address public concerns with new and existing technologies, and often industrial corporations reply that such concerns are unwarranted and that their technologies are safe and broadly beneficial. Legislatures, regulatory agencies, executive offices, the courts, and voters find themselves caught in the middle, and sometimes they also become divided over how best to develop and to regulate industry....