The committee that bestowed the Nobel Peace Prize on Mikhail Gorbachev yesterday resorted to bureaucratic language to explain its selection. Gorbachev won the prize, it said, "for his leading role in the peace process which today characterizes important parts of the international community."

The truth could have been stated more succinctly: Gorbachev changed the world.

Generations of future historians will argue about his personal role in the end of the Cold War, the liberation of Eastern Europe, the collapse of the Russian empire and the cooling of the arms race that devoured the resources of his nation and others for 40 years. Some will contend that Gorbachev himself played the critical role in all these events; others will say that he happened to be standing at the key intersection when the forces of history came blowing through town.

As the Nobel committee demonstrated yesterday, however the history is written, Gorbachev will get much of the historical credit.

On one level Gorbachev's personal contribution is clear: He was prepared to take his country -- and because of its importance, the rest of the world -- in a radically new direction. He became a celebrity, even a hero, because of his willingness to confront his country's Stalinist past and begin to tell the truth, renounce the superpower struggle for global influence, walk away from the war in Afghanistan and abandon Moscow's control over the nations of Eastern Europe.

All of these departures could be described as signs of weakness, or concessions. Gorbachev had to concede that the lies his predecessors told about the glories of communism and its eventual triumph in the world were indeed lies. He had to concede that Russia was utterly exhausted by the arms race, which -- together with a hopelessly inefficient and backward economy -- had left it staggering. He had to concede that the only alternative to letting the East Europeans go free was a kind of bloody repression that no longer seemed plausible for a weakened Soviet Union eager to improve relations with its neighbors to the West.

But if Gorbachev was acting from a position of weakness, he was not forced to make the world-changing choices he did. The first sign of his willingness to break with the Soviet past came in the realm of foreign policy.

Eight months after coming to power he traveled to Geneva for a summit meeting with Ronald Reagan, then the leading bogey man of Soviet propaganda whom some Soviet officials had compared to Adolf Hitler. In Geneva, Gorbachev signaled a profound shift in his foreign policy, declaring that he and Reagan could work together to tame the arms race and improve prospects for peace. Reagan believed him, though many others in the West remained skeptical for years afterward.

In the second half of 1986 the first meaningful examples of glasnost, or openness, appeared -- another choice Gorbachev did not have to make. Glasnost became truth-telling.

Soon Soviet writers were exploring subjects that had long been taboo, and journals of all kinds were publishing startling exposes about the Soviet past and present. This was also a contribution to relaxing world tensions. The Soviets' insistence on lying about themselves was a fundamental cause of the mistrust others felt toward them.

Another source of mistrust was the way Soviet governments had mistreated citizens who spoke their minds -- dissidents who challenged official orthodoxy. Gorbachev himself took a giant step toward calming those concerns with a single telephone call, which he made on Dec. 16, 1986.

It was a call to the last Soviet recipient of the Nobel Peace Prize, Andrei Sakharov, then languishing in internal exile in the city of Gorki. Gorbachev invited him to return to Moscow and resume his "patriotic work." Soon Sakharov was an active Gorbachev ally in the Congress of Peoples' Deputies.

Beginning in 1987, Gorbachev began to talk insistently of the need to democratize Soviet society. Again he met widespread skepticism, at home and abroad. But he was serious. He proved that in 1988 when he made clear his intention to take the Communist Party out of the day-to-day governing of the country, replacing it with new, elected political insitutions. In the amazing year of 1989 those institutions were formed. Soon afterward communism collapsed all over Eastern Europe, and the Berlin Wall came down.

Again Gorbachev played an activist role he could have avoided. He instructed the Polish Communists to join a coalition government headed by the Solidarity trade union -- a key signal to the other East Europeans that he would no longer insist on Communist control. He pressed Erich Honecker to undertake reforms in a way that signaled his disapproval of the old East German regime, encouraging Honecker's rivals.

Gorbachev quickly agreed to withdraw Soviet troops from Czechoslovakia and Hungary. His early opposition to a reunited Germany evaporated last summer. In other words, he made no attempt at all to preserve a Soviet empire.

The full impact of Gorbachev's revolution won't be known for years. The United States, for example, is just beginning to grapple with the transformation of the enemy that dominated its concerns for two generations. The new Germany that now sits astride Europe is a big part of Gorbachev's legacy, but its future is uncertain.

And in the Soviet Union, there is chaos and uncertainty. The country has been given a new politics, but struggles with the same old economics; new nationalistic energies threaten to tear the old union of republics apart.

Like Winston Churchill at the end of World War II, Gorbachev now is in danger of losing the support of his countrymen despite the enormity of the gift he has given them. That gift includes the freedom to say what they think; the opportunity to know the true history of their country; the chance to live someday in a "normal" country, to use an adjective much favored by Russians in these exciting times. None of those measures up to a regular supply of bread, meat and milk, which is an important reason why Gorbachev is in such difficulty today.

The most popular politician in the Soviet Union now is Boris Yeltsin, elected the president of the Russian republic last spring over Gorbachev's strenous opposition. In recent months, under enormous pressure, Gorbachev has had to sue for peace with Yeltsin and seek his support for the next round of economic reforms.

Yeltsin has good grounds for disliking Gorbachev, who has treated him harshly since turning against him in 1987, but in his memoir, "Against the Grain," published last spring, Yeltsin gave Gorbachev a warm tribute:

"What he {Gorbachev} has achieved will, of course, go down in the history of mankind. . . . He could have gone on just as {Leonid} Brezhnev and {Konstantin} Chernenko did before him. . . . He could have draped himself with orders and medals, which is always enjoyable. Yet Gorbachev chose to go another way.

"He started by climbing a mountain whose summit is not yet even visible. It is somewhere up in the clouds, and no one knows how the ascent will end: Will we all be swept away by an avalanche, or will this Everest be conquered?"

March 2, 1931 -- Mikhail Sergeyevich is born in Privolnoye, a rural town in the Stavropol region of southern Russia.

1950 -- Enrolls at Moscow State University in Moscow to study law.

1952 -- Becomes a full member of the Communist Party and active in the Komsomol, the party's youth organization.

1954 -- Marries fellow student Raisa Maximovna Titorenko.

1955 -- Returns to Stavropol and begins fulltime Komsomol work.

1960 -- Appointed first secretary of Stavropol regional Komsomol.

1966 -- Promoted to head the party organization in the city of Stavropol and three years later is elevated to full membership in the national Communist Party Central Committee.

1971 -- Becomes deputy of the nation's then-nominal parliament, the Supreme Soviet.

1978 -- Appointed Central Committee secretary in charge of agriculture and moves to Moscow.

1979 -- Named candidate, or non-voting, member of the ruling Politburo headed by then-President Leonid Brezhnev. Becomes a full member a year later.

March 1985 -- Named general secretary of the Communist Party following the death of Konstantin Chernenko.

November 1985 -- Meets with President Reagan for the first time in Geneva. Over the next five years, the leaders hold four summits.

1986 -- Begins his reform program in earnest, using the Russian catchwords glasnost, meaning openness and self-criticism, and perestroika, meaning restructuring. Frees Nobel Prize-winning dissident Andrei Sakharov from internal exile in the city of Gorky.

1987 -- Travels to Washington to meet with Reagan and signs a treaty to eliminate both sides' medium-range nuclear missiles.

1988 -- Calls the first Communist Party conference since the days of Stalin to press for more radical reform. In December, presides over the dissolution of the old Supreme Soviet, to be replaced by the Congress of People's Deputies and a smaller, full-time legislature, the new Supreme Soviet.

1989 -- Withdraws Soviet troops from Afghanistan and presides over new parliament that elects him president.

1990 -- Ends Communist Party's constitutional monopoly on power and moves to create a stronger presidency. Endorses moves to create a free market economy in Soviet Union.