The events that took place on September 11, 2001, in New York City are the background for a series of essays exploring the response of different cities at different times to natural or man-made disaster. How have cities coped with cataclysmic change in the urban fabric both physically and psychologically? How have they memorialized what they have lost, and how have they imagined their future? What have been the effects, in both the short and long term, of these efforts to rebuild the city?