SANTIAGO, Chile, March 10 — Ricardo Lagos barely squeaked into office here six years ago, winning just a hair over half the vote in a hard-fought runoff. On Saturday, however, he will step down as president of Chile with three quarters of the population saying it approves of his performance, according to recent opinion surveys.

As the first Socialist to govern Chile since Gen. Augusto Pinochet overthrew Salvador Allende in 1973, Mr. Lagos took office carrying a special historical burden. But by combining cautious economic policies with advances in social equality and human rights, he has built a level of respect that cuts across class and generational lines, from conservative businessmen to the rock fans who gave him an ovation when his presence was announced at a U2 concert here two weeks ago.

In a survey of 20 prominent Chilean historians, political scientists and other academics published last weekend in the conservative newspaper El Mercurio, one of his most incessant critics, Mr. Lagos" was ranked the best of the 30 presidencies the country has had since 1900. Mr. Allende, who died in the American-supported coup against him, finished second to last on the list, while General Pinochet ended up in a tie for tenth place.

"We have had an outstanding relationship with President Lagos," Secretary of State Condoleezza Rice told Latin American reporters in Washington this week, before flying here for the inauguration of Mr. Lagos" successor, Michelle Bachelet, on Saturday.

"I think he has been not just a great president for Chile," Ms. Rice said, "but he"s been really a wise and strong force for democracy and for free economies throughout the region.

"He"s been really an extraordinary figures in this period," she added.

On a continent where Hugo Chavez of Venezuela gets most of the attention, Mr. Lagos is valuable to the United States because he "embodies the other left, the successful left," added Arturo Valenzuela, who was director of Latin American affairs at the National Security Council during the Clinton Administration. "It"s not like he is a Socialist in sheep"s clothing, he has actually done a lot in the way of social programs."

Successful, stable governments are hardly the rule in this part of the world, and for a president to leave office more popular than when he entered is even more unusual. During Mr. Lagos" tenure, for example, two neighboring countries, Argentina and Bolivia, have each had six different presidents, at least two of whom were toppled by popular uprisings.

"This country is much better off now than when Lagos first came in, both in terms of economic growth and poverty reduction," said Patricio Navia, a professor at the Diego Portales University here and at New York University, who participated in the survey.

During an interview, Mr. Lagos, 68, an economist who earned a doctorate at Duke University, said that when he came to power after a decade in which the country was led by Christian Democrats, both the business class and "the military sectors were quite suspicious." He viewed his task, he said, as one of "dispersing ghosts" from the past and gaining the confidence of skeptics.

Though still not popular with the far right and his own left flank, which considers him too timid, Mr. Lagos calmed the powerful business elite by continuing the main economic policies of his predecessors: pursuing budget surpluses and programs to stimulate exports. But with copper prices at a record high and the economy growing faster than any other in South America, he could also afford to let the military acquire new weapons while investing in health, education and housing programs for the poor.

In the foreword to a recently-published collection of Mr. Lagos" essays, speeches and interviews, called "The 21st Century: A View from the South," Prime Minister Tony Blair of Britain praises Mr. Lagos for demonstrating "how the values inherited from socialism can be applied in a 21st century society." Mr. Lagos" great achievement, he adds, is that "while adhering to the basic principles of a free market economy," he "has put in place social programs which have made an impressive impact on poverty levels."

The most concrete indicator of Mr. Lagos" success in soothing the initial fears that he might be a replay of Mr. Allende is that he will transfer power on Saturday to another Socialist, Ms. Bachelet. She is the first woman to be elected president of a Latin American country who was not the widow of a political leader. Mr. Lagos promoted her ascent, in part, he said, as a way of showing the rest of the world that its perception of Chile was out of date.

"In 2002, it was still thought, especially abroad, that Pinochet was running things," he explained. "I was tired of explaining that Pinochet wasn"t in charge." When he moved Ms. Bachelet from health minister to defense minister, he said, "nobody complained, nobody said anything."

Mr. Lagos also addressed Chile"s painful past by creating a commission to investigate and report on torture during the Pinochet years and by persuading the Chilean military to acknowledge its responsibility for those abuses. He has also allowed the judicial system to prosecute General Pinochet, giving specially-appointed investigative judges both the money and independence they need to do so.

"We have had many differences with him but, in retrospect, during the Lagos administration Chile has made the most impressive progress on human rights issues as well as justice reform and freedom of expression," said José Miguel Vivanco, a Chilean lawyer who is director of Human Rights Watch Americas.. Mr. Lagos" term has been marked, too, by major social changes like the legalization of divorce and the end of film censorship. "In general, the transition agenda is coming to an end," the president said in the interview. "A few elements of healing wounds still remain, yes, but those will close with time."

Despite his socialist origins, Mr. Lagos" government struck free trade agreements with both the United States and the European Union, among others. Since the accord with Washington went into effect in 2004, Chilean exports to the United States have increased nearly 80 percent and American exports to Chile have climbed 90 percent.

Politically, though, there have been a few rocky moments in relations with the United States, most notably when Chile was a member of the United Nations Security Council in 2003 and opposed the Bush Administration"s plan to invade Iraq. That was a very popular position here, but it may have contributed to Washington"s opposition to the candidate Chile offered as secretary general of the Organization of American States in an election last year.

Mr. Lagos ended up winning that battle, which has enhanced Chile"s regional influence. But he had earlier won Washington"s gratitude by taking on, with Brazil, the leadership of a Latin American peacekeeping mission in Haiti, sparing the Bush Administration the political and military cost of direct involvement there while it is bogged down in Iraq.