MOSCOW -- The thin, bearded man who tends the elevator at 21 Red Army St. is one of the Soviet Union's "new dissidents." And perhaps not long from now, he and his generation of intellectual soldiers may inherit the mantle worn by Andrei Sakharov.

Boris Kagarlitsky, 29, is a leading member in the Club of Social Initiatives, one of hundreds of informal groups that have sprung up here in the last two years.

Sakharov, once a top nuclear physicist, was one of the Soviet Union's leading dissidents for two decades, eventually banished to the closed city of Gorki until he was allowed to return to Moscow and scientific work. Although he admires Sakharov's courage, Kagarlitsky said, "Sakharov is of another epoch, an epoch that has ended. Now his public stance is not so different from the official view of the reforms.

"The young have not lived through the Stalin crimes or the thaw under Khrushchev. We have different experiences and a different psychology and cultural background."

Groups like the Club of Social Initiatives, Democratic Perestroika and others favor a free press, civil liberties, parliamentary elections and political parties but, unlike some of their more western-minded elders, they want a genuinely socialist economy, a Scandinavian mode that features small, self-managed enterprises and an emphasis on social needs and choice.

Unlike what Kagarlitsky calls the "orthodox perestroika" program of economic restructuring backed by Mikhail Gorbachev, the young democratic socialists are not enchanted by economists close to the Soviet leader, such as Nikolai Shmelyev, who favor the use of free-market mechanisms to invigorate the Soviet economy. "That's pure Maggie Thatcherism," Kagarlitsky said. "We've never really even had socialism here. It's time we tried."

Kagarlitsky's opinions and ease with the press have gotten him into trouble. After giving an interview to the American magazine, The Nation, he was denounced last month in the pages of Komsomolskaya Pravda for attracting western publicity and being an "anti-Soviet element" during Leonid Brezhnev's era. He said he is planning to sue the paper for libel and added, laughing, "and I'm quite sure I'll win, too."

In 1982, Kagarlitsky, by then a trained sociologist and active in a group called Varianti, was among seven arrested for supporting the ideas of Western European Communist parties. For 13 months he sat without a trial in a cell at Moscow's infamous Lefortovo Prison.

"You know, this is not exactly the best prison in the Soviet Union," he said. "But the strange thing was we were allowed to read and there were a lot of good books in the library, stuff you couldn't always find on the outside." In prison he read Luigi Pirandello's plays, Karl Marx's "Das Kapital," Thomas Hobbes' "Leviathan" and the Russian classics.

"I even learned from some of my cellmates who were industrial managers arrested for taking or giving bribes," Kagarlitsky said. "From them I learned a good deal about how the economic system really runs."

Fortunately for Kagarlitsky and his friends, Brezhnev died and the new leader, Yuri Andropov, almost immediately released them. "There had been letters about us in the western press and I don't think Andropov wanted to start out his reign with a show trial."

Kagarlitsky has found it impossible to find a job as a sociologist and until last year he was denied his status as member of the Soviet sociological association. He appealed to every minor functionary he could think of, but it was not until he wrote to Gorbachev's most consistently liberal ally, propaganda chief Alexander Yakovlev, that he got a positive response. And it came in a week.

Even now, Kagarlitsky, his wife Irina and their 2-year-old son must get by on the little money he makes working the concierge's booth at 21 Red Army St. and as a free-lance film critic.

A few years ago, young people like Kagarlitsky, journalist Gleb Pavlovsky and sociologist Grigory Pelman, who were interested in democratic socialist reform, began meeting at a basement cafe in central Moscow's Arbat Street.

They considered themselves "the new Soviet left" and began investigating the left-wing movements that were so prominent at Parisian and American universities 20 years ago.

Keeping up with all the left-wing groups that have emerged since is as difficult in Moscow today as it was in Berkeley or Paris 20 years ago. In addition to the Club of Social Initiatives there is Perestroika 88, Obschina, the Che Guevara Brigade and the Young Communard Internationalists. Factionalism abounds.

"Some French friends who visited are in their forties and they say they feel like kids again at our meetings," Kagarlitsky said. "It's hard to say what our ideal is but it's not far from what was talked about during the {1968} Prague Spring."

Said Lev Timofeyev, a prominent dissident who helped start the Press Club Glasnost, "I don't know that the kids have worked out a plan, but they are succeeding in organizing. And that is very important."

One of the principal differences between the younger groups and their older, better-known Soviet counterparts is that activists like Kagarlitsky and Pelman are interested primarily in forging an alliance with ordinary people, what Russians call the narod. Many older intellectuals have openly admitted to being suspicious of an innate conservatism among the narod, but the younger activists -- be it through hope or experience -- think otherwise.

"We won't even use the word 'narod,' " Kagarlitsky said. "We don't see 'the people' as one big unknown mass that thinks as one."

Gorbachev's policy of glasnost, or openness, has helped reveal sharp differences of opinion not only in the Soviet leadership and press, but among the young as well.

Pamyat, or "memory," with 3,000 members, is the best-known group on the far right. Anti-Semitic, extremely nationalistic and known for eccentricities such as their black T-shirt uniforms, Pamyat's members tend to be bitter, petty bureaucrats and, according to Kagarlitsky, "marginal people."

"We don't like Pamyat and they don't like us," he said. "They are an example of what {psychoanalyst} Erich Fromm called the phenomenon of wanting to 'escape from freedom.' Their growth is a reaction to modernization and liberalization. They want to return to an idealized authoritarian past."

The young democratic socialist dissidents, who have an active membership of 1,500, feel no kinship with conservative emigre dissident Alexander Solzhenitsyn. And while many of the young dissidents are Jewish and support the right to emigrate, Kagarlitsky said, "most of us want to be here in the Soviet Union."

If they have an ideological godfather, it is the independent historian Roy Medvedev. His books, which are not published in the Soviet Union, combine a ruthless scrutiny of the crimes of the Stalin era and a passionate support of democratic socialism.

"But Medvedev is a starting point for us. The older people are fixed on the problem of Stalin, almost obsessed by it," Kagarlitsky said. "We younger people feel it less. For me, Stalin is an important question, but I'm also interested in things like the Third World. For the older generation, the Third World hardly exists."

The young dissidents worry that the renaissance of the informal group movement may have ended last October when the Politburo fired former Moscow party chief Boris Yeltsin. Known as the most radical, if erratic, voice supporting reform in the Politburo, Yeltsin allowed the Moscow groups to operate freely and use meeting halls and photocopying machines without interference. Now, many group members say, those days are over.

"The Yeltsin affair may have been the beginning of the end," Kagarlitsky said.