Two years ago, Saudia Muwwakkil, the director of communications for the Martin Luther King Jr. National Historic Site, invited community leaders to discuss how to mark the 100th anniversary of a 1906 race riot in which mobs of whites descended on the city's black residents.

The racial strife shut down Atlanta for four days and ended with the bodies of black men hanging from trees and streetlights. But of those Ms. Muwwakkil called, almost none had heard of it.

The riot, so contrary to Atlanta's conception of itself as the progressive, racially harmonious capital of the New South, had been erased from the city's consciousness, left out of timelines and textbooks.

Ms. Muwwakkil said she was not surprised by the response. ''I'm an Atlanta native,'' she said, ''and I had never learned anything about the riot. It wasn't taught.''

But in the months leading up to the 100th anniversary this weekend, there has been a concerted effort to correct the city's amnesia, with walking tours, public art, memorial services, numerous articles and three new books. Genealogists have found a few descendants of those involved and located the marked tombstone of one victim. Next year, the riot will become part of the state's social studies curriculum.

The rioting began on Saturday, Sept. 22, 1906, with a surge of white hysteria fomented by segregationist politicians and, more immediately, wildly exaggerated newspaper articles of attacks on white women by black men. By the time the violence ended, at least two dozen blacks had been killed and scores more injured, some taken from their homes or pulled off streetcars.

Later accounts attributed the deaths of two whites to the rioting, one of them a pregnant woman who died of a heart attack when she saw two black men torn apart by bullets.

The violence made international headlines. But in Atlanta, newspapers played down the events, reassuring readers that the ''Negroes'' had been ''disarmed and dispersed.''

In recent years, the country has grappled with the racial episodes of its past in myriad ways, including front-page apologies by newspapers, truth commissions and criminal trials. If Atlanta is late in coming to the table, it is at least partly because of the way the city sees itself: as a place that has always offered an economic salve for racial tensions.

But the auditorium was full on Friday when Carole Merritt, a historian, stood and said, ''The story of the riot has been too shameful to tell.''

Ms. Merritt was participating in a symposium at Georgia State University, just blocks from the Five Points intersection downtown where the mob had first gathered. She has written a book about the Herndon family, whose patriarch, Alonzo Herndon, became Atlanta's first black millionaire. His Peachtree Street barber shop, elegantly appointed in mahogany and marble, was one of the rioters' first targets.

The city's self-image was under construction well before the riot. The black educator Booker T. Washington had offered his ''Atlanta compromise,'' promising that blacks and whites could work together without social integration. The white newspaperman Henry W. Grady persuaded Northerners to invest in a tolerant, industrial New South.

But in 1906, the city teemed with uneasy change, full of new residents who fit into unfamiliar categories: successful black business owners, college-educated blacks, the first generation of young black men not born into slavery. During the riot, three black corpses were tossed at the base of a statue of Mr. Grady.

Though the episode is commonly called the Atlanta Race Riot, some say the name is itself a whitewash, because the word riot implies unrest by a minority group.

''It's not a riot,'' said June Dobbs Butts, 78. ''No, it was a massacre.'' Ms. Butts's father, John Wesley Dobbs, a civil rights leader, referred to the episode as ''the Horror.''

That first night, whites shot, beat or stabbed to death any black man they could catch. One victim was a lame bootblack, another a Western Union messenger. On Sunday, with most blacks huddled inside their homes, groups of whites went into black neighborhoods in search of more victims. Some blacks defended themselves with guns, driving away their attackers. On Monday, a white party entered Brownsville, a middle-class black neighborhood, and a shootout ensued, resulting in the death of a white county police officer named James Heard.

If the violence contradicted the city's self-image, the response was pure Atlanta. By Tuesday, white city officials had met with a hand-picked group of black leaders in an effort to restore order, beginning a tradition of interracial dialogue that became known as ''the Atlanta way.''

The process of forgetting began almost immediately. ''Atlanta is herself again, business is restored, and the riot is forgotten,'' one newspaper headline declared two days later.

But the riot shaped the city in powerful ways. Scores of middle-class blacks left the city, and segregation grew more entrenched.

''Interracial cooperation was not equal,'' said Clarissa Myrick-Harris, a historian and member of the Coalition to Remember the 1906 Atlanta Race Riot, which planned this weekend's events. ''It was another way of maintaining and asserting power over blacks.''

''The white elite chose who they were going to meet with in the black community,'' Dr. Myrick-Harris said, and a class divide emerged. Whites blamed the lower classes, both black and white, for the violence, and some black leaders characterized blacks who fought back as threats.

The riot also weighed heavily against assimilationists like Booker T. Washington in favor of more radical black thinkers like W. E. B. DuBois, who thought federal intervention was needed to protect blacks.

''It disproved Washington's belief that if blacks worked hard, saved money and became respectable, then whites would recognize their interest in protecting them,'' said David Fort Godshalk, the author of a recent book about the riot.

The riot helped spur the formation of the National Association for the Advancement of Colored People and was cited as a life-changing experience for people as diverse as Walter White, who became the head of that organization, and Margaret Mitchell, the author of ''Gone With the Wind.''

And its remembrance has brought a measure of pride to people like Pat Walker Bearden, who knew that her grandfather, Alexander Walker, had been in prison but only recently learned that it was because he had fired as Officer Heard approached his house. Mr. Walker had two small children and a pregnant wife. He was convicted in the officer's death.

Ms. Bearden said that while she was working on her family genealogy, she began to learn more about Mr. Walker from her father: ''Dad would always start out saying, 'Papa didn't take no mess.' ''

Photos: People gathered at the grave site of Martin Luther King Jr. on Thursday as part of this weekend's commemoration of the 1906 race riot in Atlanta. Above, descendants of those involved in the riot were on hand, including Farrow Allen, left, and Pat Walker Bearden and Yolanda Walker Simmons, who are sisters. (Photographs by Jessica McGowan for The New York Times)