A.M. Rosenthal, who died yesterday at 84, was the innovative and mercurial editor of the New York Times who led the paper through the journalistic challenges of Vietnam and the Pentagon Papers, the Nixon presidency and Watergate, and the Carter and Reagan presidencies. Perhaps the newspaper’s most important and influential editor in the 20th century, Rosenthal transformed the paper by adding a full-fledged business section and the magazine-style themed daily sections, like science and sports.

He was acknowledged as the driving force behind the Times’s decision in 1971 to publish the Pentagon Papers, a secret government history of American involvement in Vietnam. In a landmark case for journalism, the Supreme Court affirmed the right of the Times and the Washington Post to publish the papers without prior restraint by the government.

A seasoned foreign correspondent before he began working as an editor, Rosenthal reported while based at the United Nations, India, Switzerland, and on a civil war in the Congo in 1961. In 1960, he won a Pulitzer Prize for his reports from Poland, which expelled him for, in the words of its president, “exposing too deeply the internal situation in Poland.”

Returning to his hometown to take over as the Times’s metropolitan editor in 1963, Rosenthal made the decision to investigate the Kitty Genovese murder, in which a Kew Gardens woman was stabbed to death while dozens of witnesses apparently ignored her cries for help.

In 1969, Rosenthal began a 16-year stint as managing and then executive editor of the Times. He became known for his high-pressure, competitive, and some would say domineering style, and also for concrete achievements. The Times racked up 21 Pulitzer Prizes under his leadership. Faced with a declining urban circulation, Rosenthal led the Times to increased circulation among women and suburbanites, two key demographics. Yet despite paying attention to the big picture, Rosenthal was never less than a fully involved taskmaster, almost literally wading through copy as deadline approached, calling out reporters for their failings.

After stepping down in 1986 at age 65, as required by Times policy, Rosenthal became an op-ed columnist, apparently a kind of honorable pasture. For a man who had spent his entire career reporting and editing news, it was a new kind of challenge. Appearing beneath the prosaic rubric “On My Mind,” the twice-weekly column was not widely perceived as a success. It soon became known among detractors as “Out of My Mind,” for its increasingly strident rhetoric favoring the war on drugs and the state of Israel. Among fans of the column, “On My Mind” was appreciated enormously, particularly for its support of Israel on an editorial page that often took a critical line on the Jewish state.

In 1999, in an episode that remains murky, Rosenthal abruptly left the Times amid a very un-Timesian public dispute with his successor as executive editor, Max Frankel, over Rosenthal’s portrayal in Mr. Frankel’s memoirs. It was an episode that did little to credit either man, or the Times, which neglected to give any reason for Rosenthal’s departure.

Rosenthal ended up as a columnist for a rival, the Daily News. Often interviewed, he liked to say that he hoped his legacy would be a reputation for delivering honest, objective news. “In my epitaph, I want them to say, ‘He kept the paper straight,'” Rosenthal once said.

Abe Rosenthal was born in 1922 in Ontario, the son of an unlikely frontier fur trapper who mushed huskies to Hudson Bay in search of ermine. When the Depression slowed demand for fur, the family, including five sisters, moved to the Bronx, where Rosenthal senior became a housepainter. When Abe was 9, his father fell from a scaffold and died after three agonizing years. Abe spent much of his teenage years on crutches, hobbled by osteomyelitis, a bone infection.

Rosenthal attended DeWitt Clinton High School, and then City College, where he discovered a love of journalism while working on the school paper. He began working as a campus news stringer for the Times, and in 1944 was hired by the paper. He dropped out of college, and finished his degree several years later by piecing together classes in night school.

It was a year before he had his first byline, over a story about the last voyage of the battleship New York, visiting its eponymous city destined to be either demolished by “the cutter’s torch or sacrificed in research to a test of the atomic bomb.”

“In those days they didn’t hand out bylines like Chicklets,” Rosenthal told the Jerusalem Post in 1999. It was then that “A.M. Rosenthal” was born, the product of a zealous night editor, apparently intent on making his name sound less Jewish. “But all Abrahams received a second circumcision at the New York Times,” he said told the Post. “It came out ‘A. something.'”

After a period as a general assignment reporter, Rosenthal was assigned to cover the new United Nations. Arthur Gelb, a former Times editor who worked with him, recalled Rosenthal’s work habits in his 2003 memoir, “City Room”: I and the other clerks never tired of watching him at his typewriter. He was mesmerizing — like a virtuoso pianist of an action painter. He had composed the entire story in his mind before starting to type. … He didn’t pause, either to check his notes or to look up a spelling of a name, until he tapped out the last letter of the last word of his story. Not even Mike Berger wrote with such speed.”

In 1954, Rosenthal was assigned to New Delhi, where he became the Times’s correspondent in India. In later years, he would remember it as his favorite assignment. “It suddenly struck me that for anybody who was interested in India, I was the source of information,” he recalled in 1999. “When I left after four years, a secretary for external affairs told me that they had taken a study of the opinion leaders of the future, the senior students in Eastern seaboard colleges, and asked them where they got their information about India. Ninety-seven percent said from the New York Times.”

He also covered Pakistan, Nepal, Afghanistan, and Ceylon, with occasional trips to Vietnam and New Guinea.

“If I was writing for the Skudunk Bugle I wouldn’t have the influence. It’s not mock modesty, it’s reality. I’m sure that most of the correspondents know that and feel that.”

He left India in 1958 to cover Poland. Shortly after arriving, Rosenthal visited Auschwitz, and turned out an atmospheric piece very unusual for the Times of that day. Headlined, “There is No News From Auschwitz,” it ran in part:

“And so there is no news to report about Auschwitz. There is merely the compulsion to write something about it, a compulsion that grows out of restless feeling that to have visited Auschwitz and then turned away without having said or written anything would somehow be a most grievous act of discourtesy to those who died here.”

It was two years later that his excessive frankness — he labeled Prime Minister Wladyslaw Gomulka “moody and irascible” (shades of Rosenthal’s own future reputation), and reported that the premier was irritated by “suspicious peasants who turn their backs on the government’s plans, orders and pleas” — led him to be kicked out of the country. The move provoked howls from the American ambassador. The Pulitzer must have lessened the sting of the boot.

Rosenthal ended up as bureau chief in Geneva, a posting he found “utterly boring,” although he managed to liven things up with a trip to war-torn Congo.

In 1963, he returned to New York and was made metro editor, where he directed coverage of the Harlem riots of 1964 and the Kitty Genovese case, which first was printed as a simple police report. Rosenthal was told of the unusual circumstances a few days later by Police Commissioner Michael Murphy, and put a reporter on the story. Rosenthal compiled the book “38 Witnesses” (1964) about the case, which became a byword for urban moral decay.

Together with Mr. Gelb, Rosenthal also produced a slim volume about the 1965 blackout, “The Night the Lights Went Out.” Another quickie collaboration with Mr. Gelb was “One More Victim,” about the Grand Dragon of the New York Ku Klux Klan, Daniel Burros. It turned out that Burros was himself a Jew. Burros threatened to blow up the Times headquarters if the paper outed him. When it did, Burros instead killed himself. Rosenthal was not sympathetic. “Was I happy that he killed himself?” he said in 1999. “Of course not. I did not feel that we had done anything but the appropriate thing. It was he who was misappropriating his life, both in what he was doing and how he chose to end it. There were other ways he could have ended it — he could have quit!”

In “The Trust” (1999), authors Alex Jones and Susan Tifft quote Rosenthal’s shock at the shoddy prose that passed for news when he started as an editor. “I almost fainted the first time I saw raw copy,” he said. “My God, I almost threw up.” He encouraged better writing, and sent his reporters to cover colorful stories, like Mafia trials and scenes from the gay and drug subcultures. He introduced a more sociological bent, with religion becoming an actual reported beat, instead of transcriptions of sermons.

In 1969, Rosenthal was made managing editor and began to undertake the transformation of the paper that would become his primary legacy. One of the first changes was the introduction of the Op-Ed page, with regular columnists including Russell Baker, Anthony Lewis, and James Reston. This change was one of the few that Rosenthal had little to do with, and he lost the battle to have it fall under the purview of his news department; instead it would be part of editorial.

Rosenthal shook up the old boys network at the paper, too. When Mary Jo Kopechne drowned after Senator Edward Kennedy’s car overturned in a pond in Chappaquiddick, Mass., Reston, who was vacationing in nearby Martha’s Vineyard, covered the story for the Times. His story led, “Tragedy has again struck the Kennedy family.” An incredulous Rosenthal dispatched another reporter to cover the story.

Much more important for the paper’s bottom line was its reconfiguration to four sections, from the two sections that had been its format for decades. The process started in 1976 with the introduction of the Weekend section. Later came the familiar Sports Monday, Science, Living, and Home sections; many of the ideas came from magazine journalism. “We swallowed New York magazine,” Rosenthal later said. “I’ll steal an idea from anybody if it’s not nailed down.”

Ironically, Rosenthal had at first opposed expanding the paper, fearing that the business side would come to dominate editorial decisions. “Soft news” appealed to consumers and advertisers, but went against the entrenched Times news culture. Rosenthal eventually became convinced that the new sections were necessary because of new business realities — among them that people got more and more of their hard news from TV.

The paper sailed strongly into the 1980s under Rosenthal, winning Pulitzers each year for national or international reporting, including one by Thomas Friedman in 1983 for reporting from Israel. This was particularly satisfying because Mr. Friedman, a Rosenthal hire, had been the first-ever Times reporter assigned to Israel who was Jewish. It had been one of those quirky Times policies that irritated Rosenthal.

By the mid-1980s, Rosenthal’s reputation in the newsroom was being increasingly damaged. His private life was spinning out of control as he separated from his wife, a former Times secretary, and took mistresses. Meanwhile, Rosenthal refused to address seriously the issue of succession, which would become a necessity in 1987, when he turned 65. Finally, the Times publisher, Punch Sulzberger, who according to “The Trust” was offended by Rosenthal’s flaunting of an office romance, insisted he step aside in favor of a longtime Rosenthal rival, Mr. Frankel. The blow was softened by the offer of a column on the Op-Ed page. His life was in renewal; not only was there a new job, but Rosenthal soon remarried, to Shirley Lord, a British editor at Vogue and a glamorous society novelist.

Faithful readers of the Times in October 1986 could be forgiven for being shocked to find out that the paper’s editor had strong opinions that were very different from those of the paper itself. More oddly, the holder of those opinions was surprised to find he held them. In 1992, Rosenthal told the Baltimore Jewish Times that at first he “wanted people to say, ‘Gee, he writes like Russell Baker, only better.’ And I wanted to write about a different topic in each column. Once I gave up my ‘Russell Baker/different topic’ phase and the background noise of being an editor subsided, the things that interest me really surfaced. And to my astonishment, Israel was one of them.”

He also used his pulpit to broadcast strong views on the war on drugs, including opposing medical marijuana, and engaged in fraught battles with the columnists Evans and Novak and Pat Buchanan, whom he accused of anti-Semitism.

If anything, his transformation from the leader of the most salient redoubt of the liberal press establishment into a right-wing member of the punditocracy was increased by the September 11 attacks. A few days later, he wrote that America should threaten to demolish the capital cities of Afghanistan, Iraq, Iran, Libya, Syria, and Sudan if their governments did not cooperate in the war on terror.

Abraham Michael Rosenthal

Born May 2, 1922, in Sault Ste. Marie, Ontario; became a naturalized citizen in 1951; died today at Mount Sinai Hospital of the effects of a stroke; survived by his wife, Shirley Lord; three sons, Jonathan, Daniel, and Andrew, an editor at the Times; four grandchildren and four step-grandchildren, and a sister, Rose Newman.