It is characteristic of Iran's revolution that an alleged guru of the embassy student radicals is a dentist who hates practicing his profession and is a devout Moslem whose language is strewn with Marxist terminology.

However odd such eclecticism may strike Westerners, Iranians have learned to accept Habibollah Peyman's brand of radical politics whether they approve or not.

For the message of the small, 43-year old mustachioed revolutionary is simple in the extreme: the main mission of the "student movement is a continuing process -- and not something you can stop."

However outlandish such pretensions may have appeared four months ago when the U.S. Embassy was first occupied, no Iranian politician can afford today to ignore them.

The leader of the small, extreme left-wing "Militant Moslems Movement" has left his imprint on much of the captors' anti-American thinking.

The importance of the embassy occupation, he claims, was not just a formal demand for the extradition of Shah Mohammad Reza Pahavi and his money, but rather to demolish lingering ties with the United States and to mobilize the people to something approaching permanent revolution.

His goal, he said was to achieve "a purely revolutionary society with equality and classlessness."

"If the government or the Revolutionary Council want coexistence with the U.S. imperialists," he said in an interview, "that would not be possible from the students' viewpoint."

Peyman was coy about his actual role with the militants, however.

He said his influence stemmed from his writings and his friendship with many of them dating from their common fight to bring down the shah.

Speaking in a well-guarded building two blocks from the U.S. Embassy, he bristled at suggestions that he is a major influence on the captors or that he had actually visited the 27-acre compound.

In and out of jail for many years since his early youth, Peyman became a dentist, but preferred sociology and ecology. He said he holds master's degrees from Tehran University in both those disciplines.

Prevented by the shah's government from getting teaching or research posts, he said he was obliged to fall back on dentistry to earn a living.

"People believe I am a good dentist," he said with a smile. "I'm curious why."

By his own admission, his office was used in the two years before the revolution to work out strategy with his followers without arousing police suspicion.

The strongest influence on his own thinking, Peyman said, is the work of the late Ali Shariati, a non-Marxist but anticlerical Moslem philosopher who died in England in 1977 and did much to revolutionize Iranian Islamic thought and attract student militants.

Peyman said he backed the militants because they understood that their mission was not just to hold the American's hostage, but to destroy the political credibility of the "liberals" such as provisional government prime minister Mehdi Bazargan.

These Iranian liberals were the most important adversaries, he said, because they "hold the Army, civil service and the oil, the refineries. They have organization and can govern the country."

Ousting the Bazargan government was a design shared by the Revolutionary Council, he said. But Peyman's battle is "not really revolutionary." And although he voted for Abol Hassan Bani-Sadr as president, "that does not mean he can do anything he wants," Peyman said.