Successful democracies throughout history have used the technology of their time to gather information for better governance. Our challenge is no different today, but it is more urgent because the accelerating pace of technological change creates potentially enormous dangers as well as benefits. This book shows how to adapt democracy to new information technologies that can enhance political decision making and enable us to navigate the social rapids ahead. This book demonstrates how these new technologies combine to address a problem as old as democracy itself—how to help citizens better evaluate the consequences of their political choices. As society became more complex in the nineteenth century, social planning became a top-down enterprise delegated to experts and bureaucrats. Today, technology increasingly permits information to bubble up from below and filter through more dispersed and competitive sources. The book explains how to use fast-evolving information technologies to more effectively analyze past public policy, bring unprecedented intensity of scrutiny to current policy proposals, and more accurately predict the results of future policy. But he argues that we can do so only if government keeps pace with technological change. For instance, it must revive federalism to permit different jurisdictions to test different policies so that their results can be evaluated, and it must legalize information markets to permit people to bet on what the consequences of a policy will be even before that policy is implemented. This book reveals how we can achieve a democracy that is informed by expertise and social-scientific knowledge while shedding the arrogance and insularity of a technocracy.