The Secret Files of Mr. X

Over the past seven years, as reports of Brezhnev's declining health surfaced in the Western press (though never in the Communist press), Chernenko has become known as the fellow who is always next to Brezhnev when he has problems getting up from a sofa or negotiating steps. Experts currently rate Chernenko as having a 50 percent chance of succeeding Brezhnev, with Yuri Andropov, the KGB boss for the past 15 years and promoted in May as the party's theoretician, as his strongest rival. Viktor Grishin, the Moscow Party boss, is the dark horse candidate.

News of Brezhnev's critical illness hit top-secret cables in the mid-'70s. The first source was a Russian-speaking Egyptian diplomat who heard it from a garrulous Brezhnev in the hospital. Since then, Brezhnev's own complaints to Western leaders -- he is a hypochondriac -- as well as studies of photographs have suggested that he has a jaw ailment, perhaps cancer, and definitely a heart disease.

Mr. X says that Brezhnev is capable of sustained work for no more than two hours a day. From what Mr. X and his colleagues say, it appears that Chernenko is the keeper of Brezhnev's door, his appointments secretary, his valet.

"Chernenko is Brezhnev's first choice," Mr. X says. "But it is not clear if Brezhnev can dictate the succession." Mr. X believes that if Kirilenko, 75 and three months older than Brezhnev, had not suffered a stroke earlier this year, he would defeat Chernenko, 70, and 16 years his junior in years of service on the Politburo. Mr. X says that the decisive question is whether Kirilenko's camp will switch to Chernenko.

The Politburo is the party's all-powerful directorate, with 13 members at the moment, which selects its boss, the party's general secretary.

What Mr. X's index cards tell is that Brezhnev and Chernenko have worked together for more than 30 years, going back to the days when Brezhnev was party secretary of the Moldavian republic, one of the smaller Soviet republics, and Chernenko was in charge of the party's local "agitation and propaganda" department, known as agitprop, which corresponds to public relations in the West. When Brezhnev moved to Moscow in 1956, he remembered Chernenko and got him the agitprop job on the national level. In 1965, a year after Brezhnev succeeded Nikita Khrushchev, Chernenko was promoted to be chief of the general department of the Party's Central Committee -- an administrative organ that issues party cards, keeps records and handles letters. In 1978, after an unusually brief period of 19 months as a "candidate member," Chernenko was elevated to the Politburo.

The most valuable data on Soviet leaders come from Soviet newspapers, Mr. X says, "and Pravda tells you more than any other source. I read it every day." But, he cautions, one has to know how to read Pravda, the official Party paper, which is not written for the ordinary Russian, but "in the language of 'party Pravda,' which has its own cliches and subtleties." Pravda is "a court publication" observing "a Byzantine protocol" in which "forms become very rigid, and for that reason they become carriers of meaning."

But aren't satellites and spies more valuable than media analyses to size up the next man in the Kremlin with a finger on the nuclear trigger?

"We have to read the press, where he's been, who his friends are -- to get a feel for his personality is more important than computer data," says William Hyland, a former aide to Henry Kissinger. "The obvious tools are the real tools."

Hyland is a veteran of the CIA and the National Security Council, now at the Carnegie Endowment for International Peace. What really matters, he says, is whether a Soviet official has been associated with the military (as Brezhnev has been all his life) or sat at his desk making himself indispensable to his boss (as Chernenko has). Power can be measured by a leader's ability to promote people he worked with (both Brezhnev and Chernenko have excelled).

"Chernenko is a consummate bureaucrat," Hyland says. "An inside man for a very long time. He is similar to the personal aide who becomes the chief executive officer. He knows what needs to be done but has no roots and no strength of his own."

The single most significant contact Chernenko has had with an American official took place during a state dinner in June 1979, at the Soviet Embassy in Vienna. The occasion was the signing of SALT II; the dinner was in honor of President Jimmy Carter.