TWO years ago, if Boris Yeltsin had been unexpectedly taken to a hospital - as he was on Tuesday - the news would have sent financial markets into a tailspin and spread alarm throughout world capitals.
Looming large among the concerns would have been the man in line to replace the Russian president, a gray former Soviet industrial apparatchik on whom the country's most reactionary forces had pinned their hopes: Viktor Stepanovich Chernomyrdin.
This week, when Mr. Yeltsin was hospitalized, the markets barely fluttered, and international expressions of concern amounted to no more than a ''get well'' telegram from French President Jacques Chirac.
The man now in line to succeed the president? The same Viktor Chernomyrdin. And yet it is a very different man now getting used to the limelight, as speculation bubbles here about whether Yeltsin will contest next year's presidential elections, in light of his falling popularity and concerns about his health.
Since December 1992, when he was named prime minister, Mr. Chernomyrdin has done more than metamorphose from a cautious bureaucrat expected to put the brakes on economic reform into a respected ''safe pair of hands,'' committed to keeping Russia on the path to a free market.
More recently, he has emerged as a leader of courage, increasingly seen as capable of charting Russia's course into the next century.
Chernomyrdin is widely regarded as the man most likely to move into the Kremlin next year, should Yeltsin not run for re-election.
The premier's steady growth in stature has not been dramatic or by virtue of a shining vision. He has earned it more through dogged competence and hard work. But last month Chernomyrdin shot to prominence and seized the public's imagination as he engaged in two days of tense telephone negotiations - televised live across the country - with Chechen guerrillas who were holding more than 1,000 Russian hostages in a hospital in the southern Russian town of Budennovsk.
And he parlayed his success in winning the hostages' freedom into something that came close to vision. ''Budennovsk is the starting point of a new political era,'' he proclaimed after the crisis was over. ''For almost the first time in the history of the Russian state, the government put human lives above political expediency.''
This sort of rhetorical flourish is not something that he learned on his way up from his humble origins as the son of a peasant, who began his career as a pump mechanic.
Chernomyrdin joined the Communist Party as a young man, was sent to study at an engineering institute, and became an industrial overseer in the town of Orsk, near the border of Kazakhstan in Central Asia, keeping local factories on the mark as they struggled to fulfill their state quotas.
''He used to visit the plants on Sundays, when nobody expected him, and on Monday mornings he knew what was going on better than the specialists did,'' says one colleague who knows him well. ''He is a very demanding man.''
Later, Chernomyrdin went to work for the Central Committee, taking charge of heavy industrial plants, until he was made deputy minister for gas production, working from Tyumen, in western Siberia. In 1985 he became minister for gas production.
''He went through all the necessary steps in a Soviet career,'' says Sergei Kolesnikov, Chernomyrdin's speechwriter and government spokesman. ''What is remarkable is that he transformed this career. Instead of staying a minister, he turned his ministry into a joint stock company.''
That company is Gazprom, the multibillion-dollar monopoly that controls every aspect of Russia's fabulous natural gas wealth, from surveying to distribution.
Chernomyrdin took over the reins of government from Yegor Gaidar, the pace of whose radical free-market reforms proved too fast for the Supreme Soviet - the parliament then. He presented himself as a technocrat whose only task was to get the Russian economy moving.
But this image was clearly disingenuous. Nobody got to the top of the Soviet system without developing a keen political sense, and Chernomyrdin has used his political skills well to navigate the shark-infested waters of the Kremlin.
His style throughout has been measured, almost dull, marked by a disinclination to promote himself too obviously. At the same time, says Vladimir Markov, director of the government news agency Novosti, ''he has very good intuition for what is happening on the ground.''
The most important decision Chernomyrdin has made recently was to launch himself beyond the backroom politics of the Kremlin and into the public political arena by forming a new political party, Our Home Is Russia, to contest this December's elections to the State Duma, the lower house of parliament.
This move, backed both by President Yeltsin and by big money, along with a good number of local government bosses around the provinces, is a powerful bid to occupy the middle ground of Russian politics - to make rivals look like radical fringe groups.
''It is logical that he should move downstage and out of the shadows to head a political bloc,'' says Mr. Kolesnikov. ''Though I know how hesitant and tortured he was about the decision because it is always a difficult thing to change your image.''
Chernomyrdin has explained his plunge into party politics by his desire for a parliamentary majority that would make the government's work easier. But an electoral success would provide a springboard for a 1996 presidential bid.
The day Chernomyrdin became prime minister two and a half years ago, then-presidential spokesman Vyacheslav Kostikov referred to him somewhat deprecatingly as ''a very good organizer of production'' who would team well with Yeltsin, who he described as ''a politician of high status.''
Today Chernomyrdin has combined both qualities. They will make him a hard man to beat if he reaches next June for Russia's top political prize.