The release in less than two weeks of a book that criticizes Mayor Giuliani for the city’s disaster preparedness on September 11, 2001, has city officials and political analysts questioning the former mayor’s heroic public image as he gears up for a possible presidential run.

“Grand Illusion: The Untold Story of Rudy Giuliani and 9/11” (Harper-Collins), by Dan Collins and longtime Giuliani critic Wayne Barrett, says Mr. Giuliani made poor decisions in placing the Office of Emergency Management at 7 World Trade Center, issuing outdated radios that prevented the police and fire departments from properly communicating during the emergency, and failing to create a unified post for the NYPD, FDNY, and Office of Emergency Management. Much of the criticism comes from Police Commissioner Raymond Kelly.

“If Giuliani had any sense of the threat, he would have gotten out of the City Hall area,” Mr. Kelly told Mr. Barrett. “The radios would have been no problem if they had been at the same command post, if they’d been face-to-face.”

Mr. Kelly had served two years as police commissioner under Mayor Dinkins until, in 1993, Mr. Giuliani replaced him with Bill Bratton. At the time, crime was at an all-time high, and 1,927 murders were recorded for the year.

Yesterday, Mr. Kelly all but rescinded his critical comments, praising Mr. Giuliani’s response to the attacks.

“Considering the enormity of the attack, the command center’s location and other operational issues made little or no difference in the outcome that day,” he said. “The leadership Rudy Giuliani demonstrated on September 11th and the reassurance he gave the city trumped any of the procedural issues I was asked about.”

Mayor Koch said Mr. Kelly’s accusations hold water.

“I thought it was foolish to place it at 7 World Trade,” he said. “Who places an emergency office on the 23rd floor?”

He also said the outdated radios are a legitimate reason for concern. “He had an extended period of time to make the radios compatible and he didn’t do it,” Mr. Koch said.

Mayor Bloomberg, on the other hand, stood behind his predecessor. “Whatever Ray Kelly said, those are his views,” he said yesterday. “I think Rudy Giuliani did a great job running this city both before and after 9/11, and his leadership on that day really was extraordinary.”

A deputy mayor of operations under Mr. Giuliani, Randy Mastro, said, “The book is revisionist history at its worst, so it’s not going to have any effect.”

While political consultant Hank Sheinkopf said all the good press the former mayor received after the attacks will never be forgotten, he said he thinks the book will affect Mr. Giuliani’s possible bid for the presidency.

“Could it be used in a campaign to injure him?” he asked. “Well certainly, opponents would use it to injure him.”

A professor of political science at Columbia University, Steven Cohen, said it is part of the nature of presidential campaigns to dig up criticism. “If he wants to keep a positive glowing image of himself in the public, the last thing he should want to do is run for president,” he said.

Chairmen Thomas Kean and Lee Hamilton of the 9/11 Commission, when they released their book, “Without Precedent: The Inside Story of the 9/11 Commission,” said last week that they restrained themselves from asking tougher questions of Mr. Giuliani for fear of tainting his post-9/11 image.

“It proved difficult, if not impossible, to raise hard questions about 9/11 in New York without it being perceived as criticism of the individual police and firefighters or of Mayor Giuliani,” they wrote. “We did not ask tough questions, nor did we get all of the information we needed to put on the public record.”

Like Mr. Kelly, the FDNY said yesterday it has no intention of criticizing Mr. Giuliani. “We want to keep the five-year anniversary positive,” a spokesman, Seth Andrews, said. He said for now the FDNY will not comment on the issue of the archaic radios used during the September 11 attacks.

Mr. Giuliani’s spokeswoman, Sunny Mindel, said she has not read the book. “I haven’t read it, so why would I comment on it?” When asked if she would ever read it, she said, “No, we have no interest.”