The firefighters had 29 minutes to get out of the World Trade Center or die. Inside the north tower, though, almost none of them realized how urgent it had become to leave. They had no idea that less than 200 feet away, the south tower had already collapsed. Until last month, the extent of their isolation from critical information in the final 29 minutes had officially been a secret. For three and a half years, Mayor Michael R. Bloomberg refused to release the Fire Department's oral histories of Sept. 11, 2001. Under court order, however, 12,000 pages were made public in August.

On close review, those accounts give a bleaker version of events than either Mayor Bloomberg or former Mayor Rudolph W. Giuliani presented to the 9/11 Commission. Both had said that many of the firefighters who perished in the north tower realized the terrible danger of the moment but chose to stay in the building to rescue civilians.

They made no mention of what one oral history after another starkly relates: that firefighters in the building said they were "clueless" and knew "absolutely nothing" about the reality of the gathering crisis.