DAR ES SALAAM, TANZANIA -- To many people in this sleepy Indian Ocean port city, 57-year-old James Mapalala is something of an eccentric. True, it seems a bit strange that Mapalala and his wife, Hannah, live on a small patch of dirt near the middle of downtown with six noisy ducks, five chickens, three cows and a couple of scruffy dogs.

True, the lanky, white-haired fellow tends to write so many notes to himself that his baggy pants pockets often overflow with crumpled wads of paper.

But in a lethargic land where strict rule by one political party is constitutionally mandated and where public dissent is rare and sometimes stiffly penalized, this gentle man is most noted for speaking his mind. Often. He is among Tanzania's most eloquent advocates of civil and human rights and political change.

"I'm sure almost everyone in Dar es Salaam knows Mapalala and what he stands for," said C. Stanley Kamana, editor of a weekly newspaper here. "I know the government people don't think too much of him. But everyone respects his beliefs. He has made the idea of dissent an honorable thing."

At a time when popular movements for democratic change have flared across sub-Saharan Africa, from Kenya to the Ivory Coast, the ideas of free thinking and freedom of expression have gradually acquired new value and respect. For many Africans, cowed by years of state repression, the assertion of liberties and individual rights remains a new and frightening thing, however. Not to Mapalala. He is a grand master in the art of daring to differ.

The other day, Mapalala grabbed a microphone at a private hearing called by ruling party officials to discuss press freedom in Tanzania. In a booming voice, he declared the hearing a farce, saying there is no such thing as guaranteed freedom of expression in Tanzania and never will be until the government allows fair elections. The journalists in attendance applauded loudly. Party officials kept their lips tight.

Back in the 1950s, Mapalala, a building contractor by trade, was a founding member of the Tanganyika African National Union, precursor of the Party of the Revolution, which rules to this day. He was, he said, once a close friend and ally of some the highest-ranking members of the government. He said he still believes deeply in African liberation struggles and the principle of socialist self-reliance that guided former president Julius K. Nyerere, whom he admires.

But over time, Mapalala said, he grew to detest what he saw as growing official corruption and political repression -- including press censorship and jailing of dissidents -- carried out in the name of principle. "Unity and socialism were just an umbrella many of these {officials} sat under to hide the fact that they used their positions for personal gain," he scoffed, sitting back in a chair on his humble inner-city spread. "It's all lies. There is no democracy here. There is no freedom. And they can arrest you for even thinking that way, isn't that right, Hannah?" he asked.

His wife, feeding the ducks, sighed and nodded her head.

It was Hannah Mapalala whom her husband credits with saving his life. In 1986, he was detained without charge or trial, suspected of attempting to overthrow the government. His crime was circulating a petition calling for abolition of the single-party law; in just a few weeks, 320,000 people had signed.

This did not go over well with the ruling party, which faced serious problems. The economy had fallen apart and the country was about to be ousted from the International Monetary Fund. The government began arresting scores of "economic saboteurs," including merchants, dissidents and human rights activists.

Hannah Mapalala, who recalled the terror she felt upon seeing the police drag her husband away, didn't know what a habeas or a corpus was, much less a writ. But, she said, she educated herself quickly in the ways of the law, went to court and filed papers to gain Mapalala's release. She pressed the press and party officials. Finally, she turned to Amnesty International, and the human rights group began to publicize the case.

It was a tense, embarrassing time for a government founded on principles of "caring" and "fairness" that had always prided itself on its ability to maintain national peace and unity.

Mapalala was put in Dar es Salaam's central jail with hundreds of young felons, he said. He said he was regularly beaten. After 1 1/2 years, he became sick with dysentery and began to lose his sight, when state health officials found him unconscious with fever.

Soon after, Mapalala was banished to Mafia (Swahili for "nice breeze") Island in the Indian Ocean, about 25 miles off the coast. The island is sparsely populated, but tourist brochures call it a great place to fish. Mapalala, exiled there for more than a year, said he didn't see any tourists, didn't catch many fish and spent most of his time tilling a barren patch of soil, trying to grow something to eat.

"It was so lonely, it would have been easy to go a little crazy there," he said. "I just put my faith in Hannah."

In April 1989, the government "pardoned" Mapalala, even though he had never been charged with a crime. Hannah recalls her shock at feeling how skinny he had become when they embraced in Dar es Salaam a few days later.

After his long ordeal, the government probably expected the old man to pipe down. But not Mapalala. It took him about an hour, he said, to begin his crusade once more.

As the government froze his bank account and seized all his assets except the downtown patch of dirt he lives on, Mapalala drew up another multi-party petition -- he says it has more than 100,000 signatures so far -- and founded a legal defense organization he calls the Civil and Human Rights Movement of Tanzania. Mapalala says it is an association; ruling party officials call it an illegal political group.

But Mapalala persists. Recently, he took up the case of a young Tanzanian studying in China who died under mysterious circumstances earlier this year while in police custody in Beijing. The student's family, recognizing Mapalala as a champion of difficult causes, sought his advice. He promptly took the story to the local press and pressed authorities to open an inquest, prompting, he said, a brief visit to his home by several unhappy Chinese Embassy officials.

"I suppose I am a bit different. Even some of my relatives don't care to have much to do with me anymore," said Mapalala, placing his arm around Hannah's neck as she rested her head on his shoulder. "People brand me a buffoon, power hungry, a crazy old man. . . . I just do what I think is right."