Nuclear bombs in suitcases, anthrax bacilli in ventilators, avian flu, and scorchingly hot temperatures: nightmares that were once the plot of Hollywood movies are now frighteningly real possibilities. How can we steer a path between willful inaction and reckless overreaction? Cass Sunstein examines these issues in his new book, Worst-Case Scenarios. Singling out the problems of terrorism and climate change, Sunstein explores our susceptibility to two opposite and unhelpful reactions: panic and utter neglect. He shows how private individuals and public officials might best respond to low-probability risks of disaster. He also emphasizes the need to know what we will lose from precautions as well as from inaction. Sunstein concludes that if we can avoid the twin dangers of overreaction and apathy, we will be able to ameliorate--if not avoid--future catastrophes, retaining our sanity as well as scarce resources that can be devoted to more constructive ends.