For most civilized people terrorism is hard to imagine. Scenarios are concrete descriptions of events, case studies that help the imagination. Statistics inform, but are abstract. Planners and strategists, be they Colonels, Captains or Chiefs, need good scenarios, and they need to think and talk about them. Those who rely exclusively on statistics, to use a phrase popular in another decade or on another coast, don't get their consciousnesses raised; terrorism remains beyond the imagination.