Heraldo Muñoz weighed a dilemma when he sat down to write about his past, which included slinking through Santiago, Chile, with unstable sticks of dynamite strapped to his chest, girding for the insurrection that never materialized against the infamous 1973 military coup.

Heraldo Muñoz weighed a dilemma when he sat down to write about his past, which included slinking through Santiago, Chile, with unstable sticks of dynamite strapped to his chest, girding for the insurrection that never materialized against the infamous 1973 military coup.

In the ensuing decades, after all, Mr. Muñoz had become not only Chile’s permanent representative to the United Nations, but also the head of a Security Council antiterrorism committee. Accomplished diplomats are not supposed to wield explosive verbs, much less actual dynamite.

But in writing “The Dictator’s Shadow: Life Under Augusto Pinochet,” a memoir published this fall, the ambassador decided that only the complete story would suffice.

“At that time, and it’s hard to say it, but I was ready to die because I was defending a constitutional government and a cause,” Mr. Muñoz, 60, said in an interview in his airy corner office overlooking the United Nations and the East River. “That is my life, and that is when everybody was crazy in the world.”

He overcame his initial reluctance to write the book, he said, when he realized that General Pinochet had affected an entire generation in Chile and all around the world — prominent leftist politicians and advocates told him the fight over Chile had inspired them to enter public life and still shaped their outlook. It took him two years of writing evenings and weekends to finish the work.

In addition, Mr. Muñoz wanted to examine the question of whether Chile’s free-market economic miracle was really the fruit of the Pinochet period — as General Pinochet’s die-hard supporters still claim — or whether it might have occurred without such a brutally anti-Socialist regime.

Although General Pinochet unleashed free-market policies inspired by the “Chicago boys,” young Chilean disciples of Milton Friedman and other economists of the Chicago School, the dictator was forced to retrench and even to nationalize much of the banking sector with a $7 billion bailout in the early 1980s.

It was only after the defeat of General Pinochet in a 1988 plebiscite and the establishment of democracy that the real economic boom occurred, Mr. Muñoz argues in the book, with the poverty level in Chile dropping to 13.7 percent in 2007 from 40 percent in 1990.

But Patricio Navia, who teaches Latin American studies at New York University, says the book underplays the extent to which modern Chile is a creature of what Pinochet wrought. “Chile today is much more what Pinochet had in mind than what Allende had in mind,” he said, referring to Salvador Allende, the Socialist president of Chile who was overthrown in the 1973 coup.

Paul E. Sigmund, a professor emeritus at Princeton and an expert on Chilean politics, said the book’s greatest value lay in its detailed descriptions of the policy fights of the Pinochet era. “He is a remarkable combination of political activist and political observer,” Mr. Sigmund said of the ambassador.

In Chile, Mr. Muñoz has a reputation for being something of a reserved outsider; partly because he has spent so much time away in various ambassadorial posts, and partly because of his humble origins. He grew up in a working-class neighborhood of Santiago, where his father was a small tradesman who had not finished high school.

Mr. Muñoz, the first in his family to attend college, won a scholarship to the State University of New York at Oswego in 1967. He had never heard of it, but looking at the tiny version of New York State depicted on a world map, he figured that Oswego was a Manhattan suburb maybe an hour outside the cosmopolitan city of his dreams. (It is 225 miles away.)

Mr. Muñoz spent his years along Lake Ontario protesting the Vietnam War and organizing immigrant farm workers. He rushed back to Chile after finishing his degree, caught up in the political ferment unleashed in 1970, when the Mr. Allende was elected president.

He took along his American sweetheart, Pamela Quick, who had never been anywhere farther from her homeland than Montreal. Hours after their 1972 marriage, he dragged her off to an Allende rally in an increasingly polarized country. “My mother still doesn’t forgive me for that: ‘How can you be so unromantic and so politically obsessed?’ ” Mr. Muñoz said, laughing. “We were making the revolution, we wanted change and there was no time to lose.”

Only 36 people died during the Pinochet coup in September 1973, the book notes, but in the ensuing year, death squads killed some 1,900 people as the dictator set about eliminating all enemies, real and imagined. Mr. Muñoz recalls the time that he and Pamela peeked anxiously through the curtains as his leftist confederates were hauled off by General Pinochet’s henchmen. But the soldiers looking for Mr. Muñoz ransacked the wrong house.

He fled to the University of Denver to pursue a Ph.D. in international political economy. The two brightest students each year were awarded Congressional internships, and he shared the honor with Condoleezza Rice. He described his current exchanges with Secretary of State Rice as strictly professional, but he writes about her as “Condi.”

His New York friends describe Ambassador Muñoz — a thin, patrician figure with gray hair and a mustache — as an easygoing, charming host, a tireless promoter of Chilean wines and a soccer fanatic who still plays on the Chilean diplomatic team. Diplomats at the United Nations from other Latin American missions say that he is a skillful, cunning midfielder, but they snicker about the way he bosses his team around as if he were their coach. Protocol does not bend, even on the field.

“It is accepted because he is the ambassador playing among other colleagues,” said a Latin American diplomat, following protocol of his own by declining to be named. “He is never contested.”

His one physical scar from the Pinochet years is the bent middle finger on his right hand, a souvenir of a beating he received back home after he finished his graduate degree. The emotional scars are buried deeper, Mr. Muñoz said.

“He doesn’t wear it on his sleeve in terms of looking for sympathy or being bitter about it,” said Sir Emyr Jones Parry, a former British ambassador to the United Nations. “I think there is a steely determination that what came afterwards, the democratic process, had to be defended at all costs.”

His support of the right to protect, the principle by which a nation is entitled to intervene in another country to protect the civilian population from genocide, does not always endear him to ambassadors from the nonaligned orbit. But Ambassador Muñoz can be equally critical of the United States. Not surprisingly, he has some harsh wvords in his book for Henry A. Kissinger, the former secretary of state, who he complains encouraged President Allende’s overthrow and looked the other way during the subsequent bloodbath.

The Pinochet memoir is not the only book by Mr. Muñoz out this fall. He also wrote a critique of United States policy in Iraq, called “A Solitary War,” originally published in Spanish and drawn from his two years on the Security Council. The book laments that Americans do not recognize the value of the United Nations in assuring the United States’ central role in the world. In a rare flash of undiplomatic frankness, he pokes fun at President Bush’s Spanish accent.

To this day, Ambassador Muñoz said, Chileans of his generation do not entirely trust the United States as a force for democratic change in the world. The fight to end General Pinochet’s rule left a permanent mark on them. “It symbolized a sense of purpose, fighting for human rights and becoming politically active, never forgetting that democracy is feeble unless we are able to strengthen it,” he said. “That is a daily task.”

Por Neil MacFarquhar, The New York Times