e was the Elvis of science.

Women pursued him, celebrities sought him out, politicians courted him, and journalists followed him through the streets.

But, as Einstein was well aware, there was a darker posse on his trail. For many years, the Federal Bureau of Investigation and other agencies spied on him, acting on suspicions as disturbing as a tip that he had been a Russian spy in Berlin; as vague as an unease with his support of civil rights and pacifist and socialist causes; and as goofy as claims that he was working on a death ray or that he was heading a Communist conspiracy to take over Hollywood.

The broad outlines of this history have been known since 1983, when Dr. Richard Alan Schwartz, a professor of English at Florida International University in Miami, obtained a censored version of Einstein's 1,427-page F.B.I. file and wrote about it in The Nation magazine.

But now new details are emerging in "The Einstein File: J. Edgar Hoover's Secret War Against the World's Most Famous Scientist," by Fred Jerome, who sued the government with the help of the Public Citizen Litigation Group to obtain a less censored version of the file. His book will be published this month.

The new material spells out how the bureau spied on Einstein and his associates and identifies some of the informants who said he was a spy.

The agents went through trash and monitored mail and telephone calls.

Those activities seemed routine to the bureau, Mr. Jerome said.

"It's like the agents got up in the morning, brushed their teeth, opened other people's mail and tapped some phones," he said.

The investigation turned up nothing. Nevertheless, the agency dogged Einstein's footsteps until his death in 1955, even cooperating with an investigation by the Immigration and Naturalization Service to see whether he should be deported.

Mr. Jerome, a self-described "Red diaper baby" born and raised in New York City, is no stranger to the F.B.I. His father, a Communist Party official, was imprisoned for three years under the Smith Act, which made advocating the overthrow of the government a crime.

As a young journalist, Mr. Jerome covered the civil rights movement. In recent years, he has been a teacher and media consultant, founding the Media Resource Center, which puts journalists in touch with scientists. He contends that contrary to his image as a woolly-headed idealist, Einstein was a savvy and politically astute champion of the underdog who made hardheaded choices about what organizations he would support.

Einstein's political problems began as a youth in Germany, which he left in 1894 at 15, partly because of a visceral dislike of German militarization. He had just moved back to the country, to a post in Berlin, in 1914 when World War I broke out, and he made no secret of his distaste for the war. He was one of only four prominent intellectuals to sign an antiwar manifesto emphasizing the need for European unity, and he attended meetings of pacifist groups.

Einstein became an international celebrity in 1919, when observations of light bending during a solar eclipse validated his general theory of relativity, a rewriting the laws of space, time and gravity.

In the following years, Einstein lent his name and, occasionally, his presence to a variety of organizations dedicated to peace and disarmament. Such activities inspired an organization known as the Woman Patriot Corporation to write a 16-page letter to the State Department, the first item in Einstein's file, in 1932, arguing that Einstein should not be allowed into the United States. "Not even Stalin himself" was affiliated with so many anarchic-Communist groups, the letter said.

Nevertheless, Einstein moved to the United States and the Institute for Advanced Study in Princeton, N.J., in 1933, when Hitler came to power in Germany. Subsequently, his outspoken support for the antifascist forces in Spain raised hackles.

Horrified by the atomic bomb, Einstein spoke out after World War II in favor of world government. He feared the tyranny of a such an organization, he wrote in The Atlantic Monthly. "But I fear still more the coming of another war or wars."

He also helped Paul Robeson, the black singer, actor and athlete, organize a rally against lynching in 1946.

In the 50's, he made headlines by appealing for clemency for the Rosenbergs, sentenced to death for espionage, and for encouraging people not to testify before Senator Joseph McCarthy's subcommittee.

Although Einstein espoused socialist ideals, he was not the kind of man to owe allegiances or to trust mass movements.

"He was not a party animal," said Dr. Robert Schulmann, a historian who is the former editor of The Collected Papers of Albert Einstein. "Einstein was the kind of guy that was uncomfortable for all authorities. He's the kind of person you don't want in your organization."

It is hardly surprising, given that résumé, that the F.B.I. would be interested in Einstein, historians and biographers of Hoover say. The attitude was that liberalism was the first step toward Communism.

"Einstein is dangerous because he is sympathetic to the kinds of causes Communists were espousing," said Dr. Ellen Schrecker, a historian at Yeshiva University and the author of "No Ivory Tower, McCarthyism and the Universities." "They assume that Einstein is a man of the left; he's got to be dangerous."

This was not so crazy, said Dr. Richard Gid Powers, a historian at the College of Staten Island and the Graduate Center of the City University of New York and the author of "Secrecy and Power: The Life of J. Edgar Hoover." The bureau had no choice but to watch Einstein, Dr. Powers argues, especially after the war, when officials worried that they were losing a "high-stakes game of propaganda" to the Soviets as luminaries like Einstein, Picasso and Charlie Chaplin criticized American policy.

"These people were way too smart to argue with," Dr. Powers said. "The only thing to do was to keep an eye on them."

A look at Einstein's file, available at foia.fbi.gov/einstein.htm, shows more about public — and bureau — attitudes toward scientific genius than toward the genius himself. No feat seemed beyond such a man, according to the file. Through a spokesman, the F.B.I. declined to comment specifically on the file, saying it was up to the public to evaluate the material. Mike Kortan of the bureau said that under the Freedom of Information Act the agency was required to release information from "an earlier era in our history when different concerns drove the government, news media and public sentiment."