Don Miller is not an effusive man. And last night he was no different as he quietly accepted applause from guests at the Martin Luther King Memorial Library lobby. Flanked by family, Mayor Marion Barry and D.C. council members, Miller was standing before the enormous, unveiled mural depicting the life of the Rev. Martin Luther King Jr. that he had painted for the library.

"I feel fine," the 62-year-old tuxedoed artist said with a gentle smile, as he fielded yet another hug from a well-wisher after the ceremony. "Just fine."

Judy Miller, his wife, was less controlled. "I can barely talk," she said, wiping her eyes and reaching for a glass of red wine. "I'm totally overcome."

"She's a toughie," said sister-in-law Lorraine Miller. "She doesn't usually cry."

Last night's reception was a "preview unveiling" of the 56-by-7-foot oil on canvas. It is to be formally unveiled today to commemorate the first national holiday celebration of King's birthday.

Talking about the painting last week, Miller remembered one night in the 1960s in Montclair, N.J., when he was just another face to King.

"I was just one of hundreds of people who filed past to shake his hand," said Miller, recalling King's visit to Montclair High School. King had come to officiate at the ordination of the Montclair Baptist Church pastor, William Gray (now a Democratic congressman from Pennsylvania and House Budget Committee chairman).

"I didn't have much time to talk to him, but he had given a very stirring address. I had been well aware of his leadership role from the beginning of the Montgomery bus boycott . . . I knew of his powerful oratory and resourceful leadership."

A minimal meeting perhaps, yet almost 20 years later, after the demonstrations and boycotts, the 1964 March on Washington (in which Miller participated), the Nobel Peace Prize, the Memphis assassination, President Johnson's social programs and other landmarks in civil rights history, Miller found himself sleeping in King's former bed in Montgomery, Ala.

He was doing research for the mural and the pastor of Dexter Avenue Baptist Church, Murray Branch, who was helping Miller with research, had put him up in the Kings' former residence.

"Staying in the room did give me a feeling of closeness to the subject I was about to undertake," said Miller, in characteristic understatement.

That undertaking wasn't just another job. For Miller, a commercial and fine art artist who was also an active member of the Montclair NAACP and the Fair Housing Commission, it was a retroactive passage through the evolution of the civil rights struggle. And to look at the mural last night was not only to see the highlights of King's life, but also to witness the trail of two years' research by Miller into the subject.

"I consider this mural to be the ultimate medium of expression for my goals as an artist," said Miller, who estimated he has depicted "98 different items in the mural -- personalities, buildings and events." He also read 20 books on King, traveled to significant sites in Georgia and Alabama, and interviewed as many of the important civil rights participants as he could. It was his intention to go to "great lengths to make certain the events and personalities depicted in this mural were historically accurate. I feel profoundly the responsibility I have, to do what I have depicted correctly."

The predominant figure in Miller's King mural is, of course, King. Miller has created 10 portraits of the slain civil rights leader within the work, including King as a child, graduating from Morehouse College, in jail with associate Ralph Abernathy, addressing the March on Washington crowd and receiving the Nobel Peace Prize.

The mural also has images of such familiar civil rights participants as Andrew Young, E.D. Nixon, Dorothy Cotton, Medgar Evers, Jesse Jackson, Joseph Lowery and Barry (first president of the Student Nonviolent Coordinating Committee).

But he also includes some lower profile participants, such as Rosa Parks, the citizen who refused to leave her bus seat, sparking the incident that led to the Montgomery bus boycott. In the mural she is seated in the bus and staring calmly and defiantly through the window just before she is to be arrested.

Rosa Parks, Miller told last night's audience, is a "wonderfully historical person . . . who I have been in love with ever since I saw her." Another figure is Mary Banks, the first woman to show up at the first and succeeding rallies for the bus boycott throughout that year. Also pictured are "12 martyrs of the struggle," including Andrew Goodman, James Chaney and Michael Schwerner -- the three vote organizers killed in Mississippi; and the four girls killed in the Klan bombing of Birmingham's 16th Street Baptist Church in 1964.

Each element in the painting, Miller said last night, "is an emotional experience. The entire process was an emotional experience."

The mural, for which Miller was paid $200,000 for labor, research and related expenses, was Miller's idea, he said. He approached the Martin Luther King Memorial Library early in 1984, he said, because of "his respect for the public library as an important cultural institution." He was also familiar with the District's library, having painted a picture of former library president Francis Gregory, which hangs there today.

"I was well aware when I conceived this idea that libraries don't have any money. So I thoroughly researched the fundability of this project and in fact got the fund-raising drive started myself."

For Miller, the mural is the second stage in a recent change of artistic direction. After spending a rewarding 1982 in Nigeria teaching graphic arts, he resolved to "no longer do another thing that didn't absolutely fascinate me and help me to grow as an artist."

Up to that point a commercial artist, he decided to "break with the past and concentrate fully on fine art. So I painted for a solid year the subjects that were of interest to me in connection with my year in Nigeria."

At the end of the year he had a successful exhibition of his works at the New Jersey Institute of Technology in Newark. Most of the paintings were African or Afro-American subjects. It was, said Miller, "a heady experience . . .

"Then I asked myself, 'Okay, Miller, what are you going to do now?' And that's when I developed the idea to do the mural."

Miller, born in Jamaica, has always been interested in black subjects and art. His father, a railroad worker, transported the family, which included five children, to Elmira, N.Y., in the 1920s. On the eve of the Depression, the 5-year-old Miller knew he wanted to be an artist after painting a backdrop of houses for a children's play. His father, when told of his son's ambition, replied, " 'Housepainters can make a good living.' I said, 'I mean pictures of houses.' And he spent the next 20 years trying to talk me out of it."

Nevertheless, Miller went ahead with art "to the detriment of all my other subjects. I barely finished high school." After an interesting stint in World War II on the Aleutian Islands, when he was the illustrator for the island newspaper (Dashiell Hammett being the editor), Miller attended the prestigious Cooper Union college in New York. While there he met Judy, who is now director of the African American Institute at Seton Hall University, and they were married in 1952. They have two sons, Eric and Craig.

For most of his career, Miller has been drawing liquor bottles and automobiles for advertising agencies or illustrating children's books and encyclopedias. And although he could take pride in rendering the bottle perfectly, "I got frankly kind of bored."

Now the choices in his life, he said, are "qualitative." Which means he can spend more time painting at the farmhouse in Upstate New York he and his wife bought 17 years ago. And doing things like the King mural.