SO ACCUSTOMED have we become to the daily dispatches from the urban battlefront—reports of perpetual crisis, the descriptions of mayors struggling in vain against seemingly hopeless odds, the ominous warnings of growing frustrations and anger—that we are in danger of taking for granted, as though they were part of the natural order, some rather remarkable developments. By the standards of any other era, what is happening today—or more precisely, what is not happening—needs to be explained.