Soviet leadership passes to a new generation. Profile of the new leader. A self-assured Gorbachev rockets to top

A political biography of Mikhail Sergeevich Gorbachev might borrow its title from a work by Charles Dickens. ``Great expectations'' have been pinned to Mr. Gorbachev throughout his rise in the Soviet hierarchy which, by Soviet standards, was lightning fast. Now the agriculture specialist from southern Russia is the leader of the Soviet Union.

At age 54, Gorbachev becomes the youngest man to take power in the Soviet state. This shift of power to a younger generation has been inevitable since the passing of Leonid Brezhnev in 1982.

Western diplomats who have met him say that he is self-assured, well-spoken, and impressive in his grasp of facts. Moreover, he seems to exhibit little of the lack of self-confidence that, in some Soviet officials, is masked by brusqueness or even rudeness.

The tentative and cautious assessment of Gorbachev by Western diplomats is that he will prove more tractable in his dealings with the West than some others in the leadership -- and much more so than Grigory Romanov, who was thought to be his main rival for Kremlin leadership.

Gorbachev also made a favorable impression on British politicians and the press during a visit to their country last December. Prime Minister Margaret Thatcher observed that she could ``do business'' with him. Gorbachev's wife, Raisa, dazzled her British hosts.

But more important is what Gorbachev intends to do with his new status as No. 1 in the Kremlin -- and whether a younger generation of Soviet leaders will seek to set this country on a path toward major economic change.

The answers to those questions are best gleaned from Gorbachev's public speeches, from his statements in articles, and from the impressions of others with whom he has met. Taken as a whole, they indicate a plain-spoken man, impatient with lethargy or blind adherence to tradition for tradition's sake, and prone to experimentation.

While in charge of Soviet agriculture, for instance, Gorbachev once proclaimed that ``there must be fewer references to the weather and to so-called objective reasons, more order on the land, more strictness and economy in the use of machinery, fertilizer, irrigated land, fodder, financial resources . . .''

But Gorbachev's remarks also indicate a man who is committed to communist doctrine and who is a firm advocate of central economic planning.

One Soviet official, speaking before Chernenko's death, speculated that Gorbachev would set about the task of ``shaking up'' this country's rigid, centrally planned economy, because he and his like-minded supporters were forced into a period of ``hibernation'' while waiting to fully take over the leadership of the country.

But, it should be pointed out, ``shaking up'' does not necessarily mean substantially altering. Indeed, one Kremlin-watcher, also speaking before Chernenko's passing, predicted that whatever changes a new generation may want to enact, they will be ``changes at the margin,'' not at the center of this country's Communist Party and state economic planning structure.

Indeed, Gorbachev has said that ``centralism'' -- meaning state planning of the economy -- is ``the key principle in the organization of socialism's economy.''

Further, he said in a benchmark 1983 speech marking the birthday of V. I. Lenin, the founder of the Soviet state, that Lenin ``cautioned against haste in tackling economic and social tasks.''

Still, Gorbachev has criticized shortcomings in the national economy and called for ``a style of work which rules out formalism and red tape, idle talk, inertia, and sluggishness.''

He has repeatedly called for ``labor discipline.'' It is widely believed that Gorbachev had major responsibility for a crackdown on corruption, sloth, and inefficiency that took place under the 15-month regime of former Soviet leader Yuri Andropov. Some analysts expect Gorbachev to initiate a similar crackdown.

Gorbachev embodies the new generation of Soviet leadership that had not reached adulthood during the World War II and the terrors of Joseph Stalin -- events that were indelibly imprinted on older Soviet leaders.

He was born on March 2, 1931, in the village of Privolnoye in the wheat-growing area of Stavropol province of southern Russia. As a teen-ager he drove a grain harvester.

He worked at a government ``depot'' -- set up during the Stalin years -- that rented out equipment and drivers to nearby collective farms. These depots were abolished by Nikita Khrushchev in the 1950s, in yet another of the various Soviet agricultural ``reforms'' that failed to address the country's food problems.

Gorbachev, according to his official biography, was graduated from the law faculty at Moscow State University, one of the country's most prestigious institutions, in 1955.

He returned to Stavropol and became head of the Komsomol (Young Communist League), first in the city of Stavropol (in 1966) and later in the entire province (in 1970).

Although the Komsomol often serves as a sort of training ground for the Communist Party, Gorbachev was apparently something of a standout in Komsomol ranks. By 1971, he had been made a full member of the party's Central Committee.

In 1978, he was made a party secretary, with responsibility for agriculture. During the years in which he oversaw food production for the party, the country suffered a series of reverses in the farm sector, marked by disappointing wheat harvests and increasing food imports.

Some analysts speculated that the failings in agriculture under Gorbachev's stewardship were largely the result of lethargy and infighting among myriad government ministries.

Whatever the reasons, Gorbachev appears not to have been burdened with much of the blame.

In 1979, he was made a candidate (nonvoting) member of the ruling Politburo, and a full member in 1980, becoming, at age 49, its youngest member.

Gorbachev was considered a likely successor when former Communist Party head Yuri Andropov passed away in February 1984.

However, in what was apparently a blocking action by older members of the Politburo, Mr. Chernenko was elevated instead.

But Gorbachev quickly emerged as the No. 2 man in the Politburo, and in late 1984 apparently rid himself of the agriculture portfolio, perhaps in an effort to put himself in a better position for the country's top leadership post.