There is a wonderful Russian slang expression, pokazuka, which means "for show," as in the empty gestures used by Soviet officials in the past to deceive foreigners looking for signs of reform -- a small edition of a previously banned poet, for instance, of which most copies are sent abroad. A decade after leaving Moscow at the end of a three-year tour as this newspaper's correspondent, I went back to the Soviet Union eager to learn whether Mikhail Gorbachev had merely imposed a new, improved model of pokazuka or had embarked on something more profound.

The answer is that important and exciting changes appear to be taking place, at least in the sensitive areas of cultural ideology and pubic relations. But I doubt the Soviets are abandoning basic principles or beliefs. What we are seeing instead is a remarkable increase in sophistication and shrewdness -- Marxism-Leninism for the mediagenic age.

What impressed me most in a hectic week of seeing old friends and official contacts is that across the spectrum -- from the dissident or liberal intelligentsia to senior apparat-are invigorated and hopeful.

"This is the closest I've ever felt to freedom of speech," said a woman writer in her sixties who lived through the worst of Soviet artistic repression. We were at a crowded reception in a downtown restaurant hosted by the American Association of Publishers in honor of the Moscow Book Fair. Without exception, the writers, critics, translators and scholars on hand had in the 1970s found intellectual life so stifling that they envied those among them brave (or desperate) enough to emigrate. Now they spoke of opportunities. Newspapers and magazines, they said, were more interesting and daring. Film and theater had revived, and for the first time they could not keep up with all that was available and worthwhile.

I asked one distinguished scientist to compare the situation now with the thaw in the early years of the Nikita Khrushchev era nearly 30 years ago -- which produced such classics as Alexander Solzhenitsyn's "One Day in the Life of Ivan Denisovich." "That was a trickle," he said. "This is a flood."

There's no question either that the party line put forth by senior officials is much more relaxed than it used to be. Robert Bernstein (chairman of Random House) and I visited almost casually with Nikolai Shishlin, an executive of an ideological department in the Central Committee. In my time as a correspondent, no one got near this powerful institution, but this time I just called Shishlin directly. He received us in his office dressed in a natty argyle sweater and speaking good English. Far from being a stilted or ceremonial occasion, it seemed almost routine -- except that, as an old Moscow hand, I couldn't get over being in this Kremlin inner sanctum.

(Bernstein, incidentally, had twice earlier been refused visas to attend book fairs in Moscow because of his human rights activities. This time Soviet officials visiting New York had gone out of their way to say they wanted him to come.)

The most intriguing new development is that Soviets of all persuasions -- and veterans in the Western press and diplomatic corps -- see real debates under way about trends in Soviet society. The faint signals that once were the grist of Kremlinology have been replaced, it is generally agreed, by sharp differences of opinion expressed in the press or in what seem to be contradictory actions.

Organizers of the book fair clearly wanted credit for the political diversity of exhibitors and books being shown this year. Yet a "Committee of Experts" still seized more than 50 titles and kept 20 despite protests all around. One book taken was a Russian translation of "Gorky Park," the American best seller of a few seasons back in which the hero is a Moscow detective. It is baffling that a novel in which a Russian cop is portrayed sympathetically should fail to pass muster in the age of glasnost.

Reading the newspapers (including the supposedly radical Moscow News) and watching the TV news, however, I was struck by how much remains tendentious, defensive and as drearily ideological as before. Officially sanctioned propaganda can still be incredibly crude. On sale last week in the foreign ministry book stall was a volume published by the Juridical Press in 100,000 copies, "Murder in Jonestown: Crime of the CIA," arguing that the tragedy in Guyana was the work of U.S. intelligence. Prominently featured was my picture (obtained I know not where) and the assertion that, as the foreign editor of The Post at the time, I was acting undercover for the CIA and was instrumental in the massacre.

And the KGB hasn't forgotten how to be nasty either. Andrei Sakharov and his wife, Elena Bonner, have returned to Moscow from their eight years of exile in Gorki. They are in good spirits and are encouraged by Gorbachev's words and actions. Nonetheless, a day after Sakharov complained publicly about the cancelation of a French-sponsored seminar on physics at which he was to be a principal speaker, someone shattered the rear window of his car, parked in front of his apartment building. "It was just a KGB reminder," said Bonner.

I left Moscow impressed by the evident improvements and the optimism of close friends. Yet I remain skeptical about how deep the transformation really is and how long it will last.

The writer is associate publisher and senior editor of Random House.