PERCY QOBOZA died of a heart attack a week ago. He was 50. Some loads become too great for even the biggest hearts.

I met him one September afternoon in 1975 in a living room in Cambridge, Mass. Qoboza was the editor of The World, a daily newspaper in Johannesburg that had the largest circulation among South Africa's black population. Along with 17 other American and foreign journalists, he had been selected to spend an academic year at Harvard University as a Nieman fellow.

Qoboza would become the most important teacher that we encountered that year.

Not that he preached. The man we met that afternoon was a stocky, wary figure, uncomfortable beyond words to find himself dropped in the midst of a society where whites and blacks casually intermingled -- a world so alien from his.

"He was an immensely complicated, troubled person," recalls Boston University professor James C. Thomson Jr., then the curator of the Nieman program, who brought Percy to Harvard.

"Percy struggled against great tides of conflict, the greatest of which was, for him, reconciling the mystery of the cruelty and hate he faced with his strong religious commitment," says Thomson. "His sensitivity was both his great strength and great impairment. The pain of the situation was almost intolerable."

And yet, at times Qoboza's wry humor would escape from behind that thick personal armor that shielded his thoughts. Thomson recalls an exchange between Qoboza and a conservative white South African journalist, who flippantly posed the fundamental question one night at dinner.

"How's it all going to end down here, Percy, do you think?" the white journalist asked.

"In a boat," Qoboza said through a half-smile, half-leer.

"In a big boat. Just the way it began. Like the big boat that brought the white people here, a big boat will come to take them away."

That year at Harvard, Qoboza said, "forced me to look at myself, and I was surprised to find that I was an Uncle Tom." But Percy knew that to cross the line that stretched in front of him would be to put his life, and his family's welfare in mortal danger.

When he returned to Johannesburg, in June 1976, he set The World on a collision course with the government over the issue of censorship, giving extensive coverage to the bloody battles between police and demonstrators going on in the black townships outside Johannesburg.

He wrote, "For the first time in my life, I could distinguish between what is right and what is wrong.

"The thing that scared me most during my Cambridge year was the fact that I had accepted injustice and discrimination as 'part and parcel of our traditional way of life.' After my year, the things I had accepted made me angry. It is because of this that the character of my newspaper has changed tremendously. We are an angry newspaper. For this reason we have made some formidable enemies, and my own personal life is not worth a cent . . . . But I see my role and {the role} of those people who share my views as articulating, without fear or favor, the aspirations of our people. It is a very hard thing to do."

In December 1976, The World published an interview with Khotso Seatholo, president of the Soweto Students' Representative Council, a prime target of the police.

On Dec. 14, after the article appeared, they came for Percy. Months later, he told some of us about it.

First, there was the sound of an automobile motor idling in the street outside his bungalow. Although it was about 3 a.m., the vehicle's lights were off. He turned to his wife Ann and said, "It's been nice knowing you."

The next moment, his home shook from the pounding of fists and clubs on the doors. The security policy barged in with guns drawn and took him away.

At the police station, he was forced to stand for eight hours of interrogation.

"Where are the student leaders?"

"How should I know?"

"You print stories about them every day."

"They know where we are. Look in their houses."

"We looked in their houses. They are not there."

"Then ask their mothers. If they don't know, how should I?"

He was released that day, perhaps because of the protests from American and British officials and journalists.

In 1977, The World was shut down and Percy was held for more than five months without being charged. He had decided that the silence imposed by prison was preferable to the silence of those afraid to speak.

After his release, he went to work for The Post, South Africa's leading black publication until it was closed in 1980. He spent most of the next two years in Washington, as editor in residence at The Washington Star. Since 1985, he had been editor of the twice-weekly City Press in Johannesburg.

In an 1981 article, directed to white readers, he wrote: "If you sometimes get mad at me, because the sentiments I express keep you awake at night, then I am glad. I do not see why I should bear the brunt of insomnia worrying about what will happen tomorrow. If many of us can keep awake at night, then maybe we will do the sensible thing -- talk together about our joint future."

Just before his second detention, in an interview he gave in Johannesburg to The Washington Star, he said, "My fear is that when history catches up with us, there's going to be an awful lot of white people in this country who will repeat those tragic words that were said in Germany at the end of the Second World War, when every German there said, 'I did not know it was happening.' It's true that for evil to succeed it takes far too many good people to keep quiet and stand by."

The lesson he provided was the picture of a man who keeps on walking through a valley of shadows and fear, a valley that seems to offer no exit or rest, except the final rest.

Peter Behr is The Washington Post's assistant managing editor for financial news.