"He advised 12 presidents — more than a quarter of those who have held the office — from John F. Kennedy to Joseph R. Biden Jr."

With a scholar’s understanding of diplomatic history, a German-Jewish refugee’s drive to succeed in his adopted land, a deep well of insecurity and a lifelong Bavarian accent that sometimes added an indecipherable element to his pronouncements, he transformed almost every global relationship he touched.... He was the only American to deal with every Chinese leader from Mao to Xi Jinping. In July, at age 100, he met Mr. Xi and other Chinese leaders in Beijing, where he was treated like visiting royalty even as relations with Washington had turned adversarial. He drew the Soviet Union into a dialogue that became known as détente, leading to the first major nuclear arms control treaties between the two nations. With his shuttle diplomacy, he edged Moscow out of its standing as a major power in the Middle East, but failed to broker a broader peace in that region. Over years of meetings in Paris, he negotiated the peace accords that ended the American involvement in the Vietnam War, an achievement for which he shared the 1973 Nobel Peace Prize...."

Writes David Sanger, in "Henry Kissinger Is Dead at 100; Shaped Nation’s Cold War History/The most powerful secretary of state of the postwar era, he was both celebrated and reviled. His complicated legacy still resonates in relations with China, Russia and the Middle East" (NYT).

With an eye fixed on the great power rivalry, he was often willing to be crudely Machiavellian, especially when dealing with smaller nations that he often regarded as pawns in the greater battle. 

He was the architect of the Nixon administration’s efforts to topple Chile’s democratically elected Socialist president, Salvador Allende.

He has been accused of breaking international law by authorizing the secret carpet-bombing of Cambodia in 1969-70, an undeclared war on an ostensibly neutral nation...

When Pakistan’s U.S.-backed military was waging a genocidal war in East Pakistan, now Bangladesh, in 1971, he and Nixon not only ignored pleas from the American consulate in East Pakistan to stop the massacre, but they approved weapons shipments to Pakistan, including the apparently illegal transfer of 10 fighter-bombers from Jordan....

In 1975, Mr. Kissinger and President Ford secretly approved the invasion of the former Portuguese colony of East Timor by Indonesia’s U.S.-backed military...

Mr. Kissinger dismissed critics of these moves by saying that they did not face the world of bad choices he did. But his efforts to snuff out criticism with sarcastic one-liners only inflamed it. “The illegal we do immediately,” he quipped more than once. “The unconstitutional takes a little longer.”...

ADDED:

“For the formative years of his youth, he faced the horror of his world coming apart, of the father he loved being turned into a helpless mouse,” said Fritz Kraemer, a non-Jewish German immigrant who was to become Mr. Kissinger’s first intellectual mentor. “It made him seek order, and it led him to hunger for acceptance, even if it meant trying to please those he considered his intellectual inferiors.”

AND:

[B]efore returning to the United States [in 1945] he visited Fürth, his [Bavarian] hometown, and found that only 37 Jews remained. In a letter discovered by Niall Ferguson, his biographer, Mr. Kissinger wrote at 23 that his encounters with concentration camp survivors had taught him a key lesson about human nature.

“The intellectuals, the idealists, the men of high morals had no chance,” the letter said. The survivors he met “had learned that looking back meant sorrow, that sorrow was weakness, and weakness synonymous with death.”

ALSO: 

If an American president was paralyzed by fear of escalation, Mr. Kissinger argued, the concept of nuclear deterrence would fail. If the United States could not credibly threaten to use small, tactical weapons, he said, it “would amount to giving the Soviet rulers a blank check.” In short, professing a willingness to conduct a small nuclear war was better than risking a big one.

MORE:

By the time that he and Nixon took office, he argued, it was too late to just leave [Vietnam]. “If you come into government and find 550,000 of your troops involved in the battle, how do you end that?” he asked. He and Nixon needed a way out, he said, that did not discredit “the 50,000 dead” or “the people who had relied on America’s word.”