Scholars tend to resist using analytical tools to make forecasts -- if only because they are so often wrong. This book tries to reinvigorate analysis of the future by showcasing the efforts of specialists on population growth, energy, climate change, and economics. The failures of prediction in these areas have been as notable as the successes, but lessons have been learned and techniques have improved. Offering a range of scenarios, for example, is more sensible than making single predictions; the authors also suggest that more scholars should use demographic developments to predict social and economic change. (Joel Cohen takes this approach as he maps out the possible consequences of population growth for attitudes toward women, pressures on migration, and the perceived value of human life.) The most straightforward predictions are built around hunches about technological change and its impacts on politics and society -- even though the linkages are more complex than the models here can capture. The book's lesson is not that prediction is futile, but that it serves a useful purpose by stimulating human responses to avoid possible disasters.