She walks the halls of her red brick kingdom of conscience in a mauve Ultrasuede suit and matching boots. Aides flit about, awaiting commands for the busiest week of her life. There will be mad dashes to New York and Washington, little sleep, demands to bare her soul live on TV for the first national holiday to honor a black American, her husband, gunned down almost two decades back.

She pulls open the shades in a well-lit office overlooking his crypt. Below, sunlight dances off a reflecting pool and throngs mill about. Her phone rings twice; she ignores it, fluffing a chair, pacing about a room full of Chippendale, African art, portraits of her late husband and a few of the 100 plaques she has received for keeping his dream alive. Nearby hang a photo of Walter Mondale ("To Coretta, with admiration") and a signed platinum Stevie Wonder album ("Your contribution to life has added another song").

There is a serenity about her some view as regal. The Widow: eyebrows arched, her mouth in perpetual droop, her face alternately pained, aloof, beatific.

Sometimes she smiles, summoning memories with rich, unexpected laughter that belies her public image. She is aware of how she plays.

"People have the wrong impression of me," says Coretta Scott King, 58. "My husband used to say, 'Coretta, stop frowning. People think you're mean.' But it's hard for me."

She pulls her mouth back in a wide, forced grin. "See, I look silly. I feel silly. But it's the only way I can stop those muscles from frowning . That's how I get caught on TV and in photos , so that's what people think."

It's habit from years on the front lines of civil rights, from the dark days of the Deep South, from the troubles and triumphs she's seen.

"Serious-minded people just don't smile," she says, eyes half closed. "You're dealing with serious issues so you're always looking serious."

Suddenly, she is laughing again. She hears that Martin Luther King III, a k a Marty, Yolanda, her oldest, and Bernice, her baby -- three of four children (Dexter was speaking in Washington) -- were just dispatched to the city jail for protesting South African food on the shelves of a grocery chain.

Is this mother delighted over children in the slammer?

"I'm pleased," she says. "They were always taught their daddy was going to jail to help people. So they've always had a positive attitude towards jail." All were later released on $550 bond. She's almost apologetic. "Marty had to fly to California to speak about the holiday," she says.

For almost 25 years, she has been the first lady of the civil rights movement, a living symbol from a bloody era. In the early years, when Martin Luther King Jr. was leading marchers into a maelstrom of hate, she was at home, organizing behind the scenes, tending four small children, fielding death threats from rednecks who meant them.

Then he was gone, and she became self-styled keeper of the flame, carving her role from ex-King lieutenants who fought to lead his domain, championing his memory by raising money to build the $15 million Martin Luther King Jr. Center for Nonviolent Social Change here to "institutionalize his dream" and taking her place as a moral authority in her own right.

Now she is Queen, heir to his legacy, a complex woman who has tirelessly worked to marshal the political forces that finally etched Martin Luther King Jr. onto official calendars and into the history books as only the second American with a federal holiday in his honor. Her goal was to fuel the memory of his work for racial equality, equal opportunity and nonviolent social change. She doesn't expect everyone to like it.

"Martin used to say, 'You can't legislate morality, but you can at least keep me from being lynched,' " she says. "Today people may still be prejudiced, but at least they're law-abiding."

While Vice President George Bush is expected as White House emissary here tomorrow in King's home town, along with a throng of celebrities and thousands of plain folks celebrating the federal holiday for the first time, the widow of 18 years is stung that President Reagan, who signed the holiday bill into law, so far has chosen to sit it out in Washington.

"It's disturbing and disappointing," she sighs. "I had great hopes this could be a national day of unity."

She's just warming up. "What's so devastating," she goes on, "is the political climate, the lack of moral leadership, the lack of enforcement of civil rights. It's fashionable to be prejudiced now. 'Human rights' only comes up when talking about the Russians."

She frets about the "self-centered kind of philosophy being promoted today," inspired by White House apathy. "It's easy not to be concerned when we don't hear concern expressed by the highest leaders in the land," she says. "But it cannot go on forever; the tide will turn."

So it was she came to labor for an official day on which to ponder the humane values espoused by her husband, the Nobel Peace Prize winner with a big dream. "He was challenging a nation to live up to its ideals," she says.

It was a long time coming. Four days after her husband was assassinated in Memphis in 1968, a fledgling black caucus member, Rep. John Conyers Jr. (D-Mich.), began touting King birthday bills. They went nowhere, year after year, but soon the King family and other movement veterans had hopped aboard the idea. A 1971 mule train dumped 3 million petitions at the Capitol.

Grass-roots tributes and memorials fanned the notion, declarations were made, marches on Washington conducted. His widow wanted a "truly American holiday," she said, for all races, and began commuting to Washington to lobby. States began passing their own versions of King holiday bills. President Carter agreed to champion the cause, but adversaries like Sen. Strom Thurmond (R-S.C.) questioned the projected price tag in federal overtime. They were close to getting the votes, then along came the Reagan landslide and a new ball game.

Stevie Wonder released songs like "Happy Birthday" to bolster support; the King Center for Nonviolent Social Change cranked up the biggest single-issue petition drive in history. A forlorn black caucus approached The Other Side: would Rep. Jack Kemp (R-N.Y.), a conservative and unlikely champion, become a point man?

It was time to call in Coretta. "It's a powerful thing to meet Mrs. Martin Luther King Jr.," says Kemp. "It's like sitting down with Mother Teresa."

Who could refuse her? "She just poured out a sense of history, what America had to be, what this meant to the country, how all Americans could benefit," says Kemp. "That appealed to me." He also saw it as a rare opportunity for the GOP to broaden its base with blacks. "That appealed to me. I just felt like it was the right time and the right thing to do."

He rode herd on vote-getting, and, with backers like Ted Kennedy in the Senate shoving aside objections from colleagues like Jesse Helms, the King holiday bill passed in 1983. The third Monday in January was designated for the official birthday celebration.

Says Del. Walter Fauntroy (D-D.C.): "We always called her in to handle the really tough situations. She brought the moral authority of one who had suffered."

She grew up in a two-room frame house in rural Marion, Ala., 80 miles south of Montgomery, the strong-willed middle child of a tenacious black businessman, Obidiah Scott, now 85, and his wife Bernice. They lived on 300 acres his parents had carved out. Coretta picked cotton for cash and worked as a maid for white folks to earn money during hard times. And she watched her father endure the Old South with courage and dignity.

He was the only black man in the county with his own truck, sparking resentment. He hauled lumber for whites, earning enough money to buy his own sawmill, but refused to sell it to his white manager and showed up one morning to find it burned to the ground. He didn't report it -- who would investigate? -- but began packing a pistol.

"I don't think he would have ever been able to use it," she says.

Whites often stopped him on lonely roads at night and threatened to kill him. When he went off to the woods to cut timber, he often warned her mother he might not be back. Fear was an old friend, she says, preparing her for what was to come.

"But he used to say, 'If you look a white man in the eye, he can't hurt you,' " she recalls.

Just when he was about to pay off years of debt to a white plantation owner, the man rummaged in his drawer to find a "record" of another $100 owed. Her father knew it was a lie, but worked an extra month anyway without a word.

Back home, Coretta spun her Victrola with gospel and black jazz singers, attended a private high school with white teachers and followed her older sister Edythe to Antioch College. She was among only six black students there. As a student teacher, she was rebuffed by a white school, a lesson she never forgot, taking out her frustrations in the early civil rights movement -- before she met King.

In 1951, she was off to the New England Conservatory of Music in Boston, a voice major on scholarship singing side by side with classmate Leontyne Price. She wanted a career badly and scoffed when a young theology student named King declared after their first date that she had all the qualities he was looking for in a wife.

"I had my own plans, but he was so persistent," she says, warming to memories of his hot pursuit. She never wanted to be a minister's wife; it seemed so confining. "He wasn't someone you could just dismiss. If I wanted to get married, he was an ideal candidate . . ." He was a Morehouse College graduate, son of a fine middle-class family; his father was a respected Atlanta minister, "Daddy" King.

To make his case, he squired her to parties where young women flocked around him, glancing over to make sure Coretta took notice. He was studying for a PhD, and announced plans to go back to the South as a Baptist preacher.

It wasn't love at first sight, but "he grew on me," she says. "You just felt good when you were around him." Finally she said yes, Daddy King approved, and they were married in 1953, both committed to "making changes in society."

And soon they were off to Montgomery, where King took over as pastor of the Dexter Avenue Baptist Church as well as the reins of a young movement.

Their first child Yolanda was born, and three weeks later, on Dec. 1, 1955, 42-year-old black seamstress Rosa Parks was arrested for refusing to give up her seat to a white bus rider. A bus boycott began and the young pastor was drafted to take over the group protesting segregated service. Life was never the same.

He was arrested for driving 30 miles per hour in a 25 mph zone. After anonymous callers threatened to "bomb his home and kill his wife and baby," she recalls her husband sinking to his knees in the kitchen to pray. "It was a moment of weakness. He felt he'd come to the end of his rope. When he got up he said he'd heard a voice, 'Stand up and fight for justice and I'll be with you.' "

Then it happened. A bomb was thrown onto the porch of their home. Coretta and the wife of a church member ran out the back with Yolanda. No one was hurt, but blacks marched to the house with guns, ready to riot. King sent them home.

"The whole thing was very exciting," she says. "It was a great time. We felt a togetherness, that it was a cause we'd win. You just had a feeling a force was guiding and directing you, that you were part of something larger."

Suddenly, she had a sense of her own destiny. "I woke up one morning after the bombing and said, 'Now I know why we're here.' It was so clear. We were meant to be there. How do you know? You just have that strong feeling. I was being prepared for something."

He was in and out of jail; the buses were integrated by court order; another bomb was found on their porch. Time magazine put King on its cover in 1957. Federal troops were sent to Little Rock, and a crazed black woman stabbed King in the chest in Blumstein's department store in Harlem as he autographed his book. "It had meaning too," Coretta said. "We were being prepared."

Only once did she break down in public, friends recall. It was 1960 in a De Kalb County, Ga., courtroom. A judge sentenced her husband to four months in prison for driving with expired license plates and without a Georgia driver's license. She was pregnant and feared he would be killed doing time at the state penitentiary in Reidsville. His sister Christine began to cry first, then Coretta. Daddy King scolded them. "You don't see me crying do you? You've got to be strong."

They were the last public tears. "I never saw Coretta break down after that," says Christine King Farris, her sister-in-law. "It was the only time."

When King went to jail in 1963 in Birmingham, she was recovering from surgery after the birth of their fourth child. She was frightened; she had not heard from him. A call was put through to President Kennedy. Attorney General Robert Kennedy called her back. He dispatched the FBI to check on King's condition. Fifteen minutes later, she got a call from her husband.

The rest is etched in the history books: the Nobel prize, Medgar Evers' assassination, the march on Washington, the "I Have A Dream" speech, the bombing of King's brother's home, the Birmingham church bombing that killed four young girls, the Kennedy assassination King saw as a preview of his own, the bodies of civil rights workers Chaney, Goodman and Schwerner found in Mississippi, the Unitarian minister beaten to death by white segregationists in Selma, the Selma to Montgomery march, Viola Liuzzo's murder, the Newark riots and, finally, James Earl Ray in Memphis.

Even when her husband was shot, and she raced to catch a plane to Memphis, she kept her composure when told he was dead. She toughed out the funeral, too, breaking down only once when she heard an old tape of her husband's sermon.

"She has strength, tenacity," says her daughter Yolanda, who remembers that day. "I said, 'Mother, you're so strong and I know how hard it is for you.' She put her arms around me and said, 'But you are going through it, too.' She has the ability to combine a hard-as-nails personality with warmth."

But those years seeped into her bones, say friends, giving rise to the tough shell she often wears that can make her seem forbidding. It's also a question of roots. "Black women in the South were brought up to feel they couldn't express their emotions because if you did, you were vulnerable, someone could harm you," says close friend Jean Young, Atlanta Mayor Andrew Young's wife, who grew up in Marion too. "So you developed a protective shield."

Around her late husband, though, "she was like putty," says one friend. "He used to tease her. They were playful. He was very macho. He would say, 'Coretta, now go get me some food.' His word was law."

She seemed unperturbed as admirers flocked around him, say friends, but he was often jealous of her. Once she donned a dress he deemed too low-cut. "You're not going out in public in that!" he said. She wore it anyway; she could not be moved -- against her will.

Sometimes she wonders how she managed to raise four children alone. "When I look back, I don't know how I made it, four kids and all," she once said. "But I took it very well, all those trying times, like the assassination, you kind of accept that, because you have been expecting that."

As she quicksteps about her domain, a red brick expanse built with donations to preserve her husband's memory and movement history and to foster programs teaching nonviolent social change, she pauses for requests for autographs and photos.

"I'm sorry, I've got to go somewhere else," she tells a group of quilt-makers who beg for a group shot. She is late, but she can't say no. Click. Click.

"I've seen you a thousand times on TV," says Cathy Maness, 37, a statuesque black teacher for a local business college, "but this is the first time I've seen you in person." Click.

Schoolchildren stare, agape over the celebrity. "I've never met her," says Audrey Howard, 12, on a class outing, "but I think she's a terrific woman."

Others hang back, put off by a royal aura. "Young black women liken her regalness to Lena Horne," says ex-TV reporter Maynard Eaton, who covered her for eight years. "They admire her but feel she's not all that warm. But to middle-aged women who've stood by their husbands and lost them, she is the matriarch who has carried on."

She has other critics, too, who see the gleaming center as a blasphemy of her late husband's dream. Located in the midst of a poor black neighborhood, it has no outreach program except a day-care center.

"Poor people have a morbid view of the center," says City Councilman Hosea Williams, a former King lieutenant. "They feel alienated by it. It's a tragedy when he gave his life for and worked for poor people . . . there are no programs that really relate to poor people."

"We don't do soup lines," says Isaac Farris, 23, a staffer and King nephew, whose "The Dream Lives" sweat shirts are expected to raise thousands of dollars for the center. "The idea is to keep up the philosophy and the spirit. We have a prison project to teach a nonviolent way of life. We have a day-care center . . . People who complain don't understand the mission of the center.

"People ask, 'Where did that $9 million go that you raised?' " he goes on. "If they want to know, they need to come over here. It's in the bricks. But there's a perception the King family is living off half that."

As president of the center, which draws a half million visitors a year and is the city's biggest tourist attraction , Coretta King takes no salary, nor do her children. She lives off royalties from her autobiography, her late husband's writings and speeches.

She lives for her work, say friends, and for her children, and when it comes to fund raising, she can summon a disarming charm, as Henry Ford II found out. He agreed to head the center's fund-raising campaign after he met her at Detroit Mayor Coleman Young's home several years back.

"You know I want to help, Mrs. King," he said. "I'm trying to think of a way."

"I know how," she said.

"How?"

"Ask your friends to help."

"It was amazing to watch her go head to head with one of the sharpest businessmen in America," recalls Robert L. Green, former president of University of District of Columbia and a close friend.

"She plays a vital role," says Mayor Andrew Young. "She campaigns for black and white officials. If she hadn't been there, none of this would have happened. There would be no center, no official holiday."

Adds Stony Cooks, a consultant who runs Young's nonprofit research firm: "Who can you evaluate her against? Mrs. Whitney Young? Mrs. Ralph Bunche? On the white side you have Jackie Onassis? Even Eleanor Roosevelt didn't memorialize her husband after he died. The government did it. No wife of a leader has done what Mrs. King has done."

Friends say she has little social life. She only lets her hair down with close friends, taking an occasional trip to Jamaica to relax, cooking at home, perhaps taking in a movie like "The Color Purple," as she did the other evening with her children. "You won't see Coretta King boogaloo," says Walter Fauntroy.

She may rekindle her singing, she says, perhaps cut an album next year. And she wonders, at times, if she were to remarry, whether it might damage her mission to carry on the memory of her late husband.

"It might," she concedes, aware of the unique status and access afforded the widow of the slain civil rights leader. But she doesn't rule it out.

"I don't know," she says. "Whatever God wants me to do . . . will happen, however I can best serve the cause . . . Martin said a person who serves a cause doesn't need a family. It requires so much time and energy . . ."

It's getting dark outside, there are speeches to write, meetings to attend. She stands, straightens her jacket. "It may never happen," she goes on, "but even if it doesn't, I've had more fulfillment in my life than most people ever have, and for that, I am grateful."