NEW YORK -- Suddenly, and with no advance warning to the audience, Salman Rushdie emerged from his life in hiding last night and implored an electrified assembly at Columbia University not to forget that he remains hostage to an Iranian sentence of death.

"Free speech is the whole thing, the whole ball game," Mr. Rushdie told an audience that had come to the Graduate School of Journalism's salute to the First Amendment and Justice William J. Brennan Jr.

"Free speech is life itself," he said.

He finished his speech and then, just as suddenly as he had arrived, he stepped off the podium and disappeared, back to the secrecy that has marked his life since Feb. 14, 1989, when Ayatollah Ruhollah Khomeini condemned Mr. Rushdie's book "The Satanic Verses" and called for the writer's death.

This was Mr. Rushdie's first trip abroad and his first public appearance outside Britain since the ayatollah's decree -- the fatwa, Mr. Rushdie repeatedly called it -- and since the Iranian government offered a multimillion dollar reward for his assassination.

In an interview earlier yesterday, Mr. Rushdie spoke about his decision to come to the United States now, about trying to find a way out of his captivity and about the pain of losing his "real life," of not watching his son grow up.

The interview was held in a Manhattan hotel under the condition that its exact name and location, and the pseudonym under which he is registered, not be revealed. Like most of his life in hiding, much of this visit remains secret.

Mr. Rushdie looked remarkably composed for a man flouting a death warrant by flying across the Atlantic and preparing to stand and speak before an audience of hundreds.

"I felt I needed to talk to Americans as well as British people," said Mr. Rushdie, who has made several unannounced public appearances in England, "because the one thing about this is that it is not a parochial matter."

The dinner at Columbia University, celebrating freedom of speech, he said, seemed to him the right opportunity to appear in the United States.

"It seems to me that what's happened around me in the last thousand-odd days is a kind of parable about liberty," he said. "It's about the importance of it and the danger of it.

"And so to be asked to speak at an event which commemorates one of the great pieces of libertarian legislation seemed like the correct place to say, to use an old line, that the price of liberty is eternal vigilance, that if you don't look out for and constantly redefend the rights you think you have, you lose them."

Mr. Rushdie said he had been longing to come to New York for a while, but U.S. authorities had discouraged him, saying that such a trip could endanger delicate negotiations over the fate of Americans being held hostage in the Middle East.

The recent release of the remaining Americans "unloosed my tongue," Mr. Rushdie said. He added that U.S. officials were "still not thrilled by my coming here."

For a man who has spent the last 2 1/2 years shuttling between safe houses, often not knowing himself where he was, arranging a trip abroad was a logistical nightmare.

"To arrange something like this for me requires an awful lot of people to cooperate and help," he said. "Now is when they were able and willing to do so."

Mr. Rushdie said he was trying, against logic and circumstance, "to have a life." But, he said, gesturing to the security operation surrounding him, "so far, it's still not my life. It's not a real life. In real life, you don't have 20 men sitting outside your door and pads on your windows."

But after lying low at the beginning of his ordeal, Mr. Rushdie has begun to be more vocal, making more public appearances and " condemning those who condemned him.

He said that by rousing public sympathy, he hoped to influence politicians to insist that any improvements in relations with Iran depended on it rescinding the decree against his life and the reward.

"Lifting the fatwa, canceling of the offer of a bounty, would take the professionals and the mercenaries, the soldiers of fortune, out of the picture," Mr. Rushdie said. He said that while Muslims might try to kill him out of religious zeal, the reward attracted a wider, more dangerous network of professional terrorists.

"If the fatwa were removed, I would face the problem of a minor pop star," he said. "A few people who did not accept that the decree was revoked might see me as a target. I can deal with that, with being careful that way. But I cannot deal with terrorism on my own. I need help."

In his speech, he said he felt as if trapped in a bubble, "simultaneously exposed and sealed off."

"For many people, I've ceased to be a human being," he said. "I've become an issue, a bother, an 'affair.' "

Mr. Rushdie lamented that people had failed to see that he was the victim of religious persecution.

In fact, Mr. Rushdie said, he is a member of the most vulnerable minority. "What minority is smaller and weaker than a minority of one?"

The danger of such persecution, he said, is not only that he himself must live his life in isolation and fear, deprived of basic freedomsand simple pleasures. Instead, the real danger of stifling freedom of speech, he said, is that ideas die.

"Those who do not have power over the story that dominates their lives," he said, "power to retell it, rethink it, deconstruct it, joke about it, and change it as times change, truly are powerless, because they cannot think new thoughts."

Mr. Rushdie said that as he watched the negotiations for the release of Western hostages, he felt as if he were aloft in a leaky hot-air balloon with them. If a decision ever had to be made about which passenger had to be sacrificed to save the craft, he said he felt, "I'd have been the first to be pitched out of the basket and into the abyss."

He said he had watched with a mixture of relief and envy as the "other" Western hostages were released from captivity and reunited "with their own, free lives."

"I rejoice for them, and admire their courage, their resilience," he said. "And now I'm alone in the balloon."

But in the interview and in his speech, Mr. Rushdie said that he had never regretted writing "The Satanic Verses." To the contrary, he said in his speech that the book "must be freely available and easily affordable, if only because if it is not read and studied, then these years will have no meaning."