THE MAN WHO CHANGED THE WORLD: The Lives of Mikhail S. Gorbachev, by Gail Sheehy, HarperCollins, 401 pages, $22.95.

“The eyes of Gorbachev burn with the fever of a man who sees his own world upside down, a leader who … dared to try to fashion a new style of leadership,” writes award-winning author Gail Sheehy in her brilliant, probing biography of the paradoxical risk-taker who rose from the low level of Cossack peasant to the leadership post of president of the Soviet Union. “Single-handedly,” continues the contributing editor of Vanity Fair magazine, “he transformed the image of the Soviet Union in the eyes of the West from a dangerous expansionist bear to a sympathetic if competitive partner.” But who is he really, this putative partner who dons and discards masks with such ready facility? To learn the truth about Gorbachev the child, man and leader, Sheehy made four trips to the Soviet Union, one lasting the better part of a year. During this period she interviewed 102 key Soviets and more than 50 American and European experts; journeyed to his birthplace; and pieced together his student years at the Moscow State University, where he met and married the astute, aloof Dr. Raisa Maximovna Titorenko.

Until now, and by design, the background of the charismatic Gorbachev has been veiled in mystery, and the author understood from the start that he wanted it kept that way. So when she delved into his past it was with the knowledge that she had penetrated terra incognita in pursuit of a phantom. A phantom who had wooed and won the trust of global heads of state; who with chameleonic skill could change his political coloration with opportunistic ease, as he did in December 1989 when he disingenously confided to Prime Minister Thatcher, “I’m not sure I’m a Communist anymore,” and followed this a few weeks later from the podium of the second National Congress of People’s Deputies in Moscow with the fervent pledge: “I am a Communist, a convinced Communist!” It was also at that same Congress, in direct contradiction to his own policies of perestroika and glasnost that he gave his wholehearted support to a heatedly debated article guaranteeing the dominance of the Communist Party.

One of Sheehy’s field trips took her to the Russian steppe of Stavropol in whose far western corner, on the outskirts of a small village called Privolnoye, baby Mikhail Sergeyevich Gorbachev had come into the world on March 2, 1931. His parents noted at once, and with consternation, that the forehead of the infant was stained with a blood-red birthmark. There was little time to dwell on this, however, because other, much graver matters had intervened. Terror had swept over the steppe, in the wake of Josef Stalin’s enforced system of farm collectivization. Many of the farmers, descendants of Ukrainian Cossacks (including Mikhail’s ancestors), resisted and Stalin starved them into submission. Six million families in the Stavropol region fell victim. In Privolnoye alone, the terrorist tactic annihilated the population by one-third. One of the resisters was Mikhail’s paternal grandfather. He was dragged of to the gulag, a family secret whose shame has weighed on the grandson all his life. On the other hand, his maternal grandfather, Gopkalo, collaborated with the Stalin regime and flourished. What is more, Gopkalo used party connections to advance his grandson’s interests.

Which reaped the greater rewards, principle or compromise? Gorbachev opted for what the author describes as a style of mental acrobatics peculiar to Soviet man — “doublethink.” He recognized conviction but walked the daring high-wire act of compromise, “moving in one direction and, while everyone is holding their breath … in a flash he flips in midair and begins moving in the opposite direction.” By dint of hard work and a knack for currying favor with the village party officials without appearing too toady, young Gorbachev was singled out for the Red Banner of Labor Award, an honor that gained him admission to the elitist Moscow State University, mecca for the cream of Soviet youth. There, through a coolly plotted maneuver, he wrangled the coveted job of class Komsomol organizer. In another bold move later on he captured the prize of his life, the hand of Raisa Maximovna Titorenko, “the secret weapon,” avers Gorbachev’s brother, “that boosted Mikhail to power.”

Of the book’s six sections, it is the penultimate one — “Dictator for Democracy” (1989-1990) that dissects the era when Gorbachev’s policy of perestroika swept like a tornado over the already tottering Soviet Union, threatening it with ruin. Gorbachev responded boldly by “orchestrating his own coronation” as president of the Soviet Union. In the final section, “Red Star Falling,” Sheehy chronicles the triumph of Boris Yeltsin when he snatched the presidency of the Russian parliament from Gorbachev who had counted heavily on gaining control of the Republic of Russia, an area twice the size of the United States. What lies ahead for the Nobel Peace Prize winner? “(He) could remain in a position of leadership for some years,” guesses Sheehy, “although his actual power is likely to be reduced to that of a ceremonial head of state.”

The drama of the Soviet Union is far from finished. Running though its maze is the scarlet thread of Gorbachev’s influence on its history. And Sheehy suggests at the conclusion of this richly textured biography that, consistent with the split personality he appears to possess, Gorbachev will be remembered after his political death as the man who changed the world and lost his country.

Bea Goodrich’s reviews are a regular feature in the monthly Books in Review section. She also writes a review column and is the author of the award-winning nature story series, “Happy Hollow Stories by Judge Tortoise.”