He has been described as "the Hitler of Cambodia," a genocidal tyrant whose brief but brutal rule claimed more than a million lives. Yet the man who terrorized his country in the 1970s and haunted Cambodians' memories for years afterward struck those who met him as modest, soft-spoken, almost gentle in his countenance, a reclusive figure who shunned the trappings of power even as he exercised it with devastating consequences.

The incongruity was part of the enigma of Pol Pot, who died Wednesday night in the jungles of northern Cambodia -- apparently of natural causes -- while being held under house arrest by former followers who had turned against him. He was 73.

Unrepentant to the end, Pol Pot had created a reign of terror in the name of establishing a pure communist society in Cambodia. During his rule from April 1975, when his Khmer Rouge guerrillas marched into the capital, until January 1979, when Vietnamese forces deposed him and installed a client government, he forced millions of Cambodians to evacuate the cities and perform hard labor in the countryside, abolished money and commerce, banned religion, suppressed family relationships, dismantled education and health care and shut the country off from the outside world.

Untold thousands of Cambodians were executed, often bludgeoned to death with farm implements in the "killing fields" that became synonymous with Pol Pot's rule. Many more died of starvation, disease and overwork. The regime left a legacy of death and ruin from which the country is still struggling to recover.

But in an interview with an American journalist last year, an ailing Pol Pot proclaimed that "my conscience is clear" and that everything he did was "for the nation and the people and the race of Cambodia."

Although he was most often identified with radical communism, he was also motivated by a deep-seated hatred of Cambodia's historical adversary, Vietnam. Despite Hanoi's earlier support for his movement, Pol Pot remained obsessively suspicious until his dying days that his much more populous neighbor intended eventually to swallow Cambodia and eradicate its Khmer race.

Born Saloth Sar in January 1925, Pol Pot was the eighth of nine children in a well-off farming family in central Cambodia's Kompong Thom Province. A cousin and a sister were consorts at the royal palace in the capital, Phnom Penh, and Pol Pot was sent there as a child to study at a Buddhist pagoda. By all accounts, he was a pleasant boy but otherwise unremarkable. As his estranged brother, Loth Suong, recalled, "the contemptible Pot was a lovely child."

In 1949, Pol Pot won a scholarship to study "radio-electricity" in Paris and set sail for France with a group of students. One of them, Mey Mann, remembered Pol Pot as a joyful and friendly "bon vivant" who showed little interest in politics. But the young expatriate soon was drawn to Marxism, immersed himself in reading and reportedly joined the then-Stalinist French Communist Party. He neglected his studies, lost his scholarship and returned to Cambodia in 1953.

According to his own account, the transformation came when he went home and was shocked to find that his family had fallen on hard times. A once prosperous uncle had become a rickshaw puller, and other relatives had lost their land and livestock. "What influenced me most was the actual situation in Cambodia," Pol Pot told American journalist Nate Thayer last year.

Pol Pot, still known then as Saloth Sar, subsequently became a teacher and married Khieu Ponnary, an austere fellow instructor and dedicated communist several years his senior. What influence she may have had on him remains unknown. She later went insane during Pol Pot's rule and was institutionalized.

After years of secret communist activity in Phnom Penh, Pol Pot rose to the leadership of the underground movement in 1962. The following year he fled to the countryside to escape a crackdown by the government of Prince Norodom Sihanouk, who dubbed the revolutionaries "Khmers Rouges," or Red Khmers.

Why he became the communist movement's leader has never been clear. He lacked the academic credentials of some of his contemporaries, but he was a mesmerizing speaker who was popular with his students.

Ensconced in the Cambodian northeast in an isolated jungle base protected by Vietnamese communist guerrillas who were then his allies, Pol Pot and his followers concocted a strange ideological brew of Marxism and what one scholar described as "badly digested Maoism." During this period Pol Pot was apparently influenced by a five-month trip he made to China at the beginning of Mao Zedong's Cultural Revolution and his economic "Great Leap Forward." It was marked by the partial evacuation of Chinese cities and purges of "class enemies."

Pol Pot's guerrilla war received a major boost in 1970 when Sihanouk was deposed by Lon Nol, the head of a military government backed by the United States. The prince then threw his support to his former communist foes, and the Khmer Rouge gained thousands of recruits. The forces of the corrupt and inept government steadily lost ground, U.S. military support was cut off, and the Khmer Rouge surrounded the capital. On April 17, 1975, Pol Pot's forces drove into Phnom Penh, ignoring a request from Hanoi to delay the capture until the Vietnamese communists had taken Saigon.

Pol Pot then launched his own version of the "Great Leap Forward," but with an apparent determination to jump even farther. The Khmer Rouge promptly emptied the cities, viewed as breeding grounds of capitalism, and began slaughtering old-regime soldiers and officials. The aim was to establish an agrarian Utopia in a single giant bound over the various stages of Marxist development. It was "Year Zero," and people were entirely expendable.

As the Khmer Rouge turned society upside down, one of the most bizarre features of Pol Pot's rule was the power given to children -- including pre-teens who had been indoctrinated in the new ideology, turned against their families and taught to "harden their hearts" toward their countrymen.

But soon the revolution began devouring its own children, as Pol Pot launched repeated purges of those he believed were plotting against him or working for his Vietnamese or American enemies. Thousands were tortured into making "confessions" at Tuol Sleng, a Phnom Penh school-turned-jail whose director reported to Pol Pot.

In an interview last October with Thayer in the Khmer Rouge stronghold of Anlong Veng, however, Pol Pot claimed that Tuol Sleng, now a museum dedicated to the victims of Khmer Rouge genocide, was an invention of the Vietnamese. As for the thousands of skulls displayed there and at "killing fields" memorials, he said, "they are smaller than the skulls of the Khmer people."

After he was driven from power in 1979, Pol Pot sought to defend his rule, then dropped from public view as the full horror of it became clear. He retained the title of Khmer Rouge military commander as his guerrillas battled the occupying Vietnamese, then "retired" in 1985 to head an obscure institute. But there was no doubt that he remained the movement's de facto leader, scholars said, citing defector accounts. Pol Pot remarried around 1987, and his young wife, a Khmer Rouge porter, bore him a daughter. Operating in strict secrecy, he managed to hold the movement together despite repeated Vietnamese offensives. A turning point came with a U.N.-sponsored peace process that cut off Chinese military support to the Khmer Rouge and led to Cambodian elections in 1993. In a split over whether to participate, Pol Pot sided with hard-liners in favor of a boycott. Wracked by defections, the movement then began disintegrating, and Pol Pot moved to the hard-liners' stronghold in Anlong Veng.

His political demise came last year when, after one bloody purge too many, he was captured by Ta Mok, a senior Khmer Rouge commander he had ordered killed. His captors later put him on trial, not for his genocidal rule but for "treason" in ordering the June 1997 massacre of former Khmer Rouge defense minister Son Sen and his family. He was sentenced to "life imprisonment" -- effectively house arrest near the Thai border north of Anlong Veng. CAPTION:Key Events in the Life of Pol Pot 1949-51: In his early twenties, Saloth Sar, later known by his nom de guerre, Pol Pot, goes to Paris on government scholarship and becomes absorbed with communist ideology. 1953: Pol Pot sets up communist party, known as Khmer Rouge, after Cambodia's independence from France. 1960-63: Pol Pot becomes party leader, flees to jungle to escape repression by Cambodia's ruler, Prince Norodom Sihanouk. 1967-68: Khmer Rouge take up arms in support of peasants against government. Army suppresses insurrection. 1970: Civil war begins after right-wing coup topples Sihanouk, who joins the Khmer Rouge to fight resistance war. 1975: Khmer Rouge seize power; Pol Pot serves as prime minister. Khmer Rouge begin experiment in agrarian communism, during which 2 million people die from starvation, overwork, execution. 1978: Vietnam invades Cambodia. Pol Pot and his Khmer Rouge are driven into jungle. 1991: All Cambodian factions, including Khmer Rouge, sign peace agreement. 1993: Khmer Rouge boycott U.N.-supervised election in which royalists win, but former communists push their way into government. 1994: Hundreds of Khmer Rouge guerrillas surrender during government-declared amnesty; others, including Pol Pot, continue war against government. 1996: In August, government announces Khmer Rouge breakup. Pol Pot's brother-in-law, Ieng Sary, leads 10,000 guerrillas to defect. In June, Pol Pot reportedly orders top general, Son Sen, and his family killed; hard-liners split into factions. Later that month, former comrades take Pol Pot prisoner. 1997: A "people's tribunal" held at the Khmer Rouge's last stronghold in northern Cambodia denounces the leader for his crimes. In October, Pol Pot speaks to Western journalist for first time in 18 years, telling reporter Nate Thayer that his "conscience is clear." 1998: In April, United States offers assistance in any effort to bring Pol Pot before an international tribunal. April 15, Pol Pot dies. SOURCE: Associated Press, "Brother Number One," by David P. Chandler