This evening, when friends, colleagues and Kennedy family members gather in the Russell Senate Office Building Caucus Room to bid farewell to Melody Miller, a longtime aide to Sen. Edward Kennedy (D-Mass.), the venue will have sentimental significance.

In that room, Miller, then 23, remembers hugging “one of the big marble columns” when then-Sen. Robert Kennedy (D-N.Y.) announced his presidential bid in March 1968. It’s also the same place where nearly a decade earlier his brother, then-Sen. John Kennedy (D-Mass.), launched his presidential candidacy.

“That room is very special for me,” Miller says, her eyes briefly moistening. “I can think of no more special room from which to depart.”

Miller is retiring after four decades of service to the Kennedys, including nearly 37 years with the current Sen. Kennedy. In the Senator’s Washington office, only Carey Parker, Kennedy’s legendary legislative director, has seen anything approaching that length of service. Parker has been on staff since 1969.

But Miller’s experience with the fabled political family goes beyond the current Senator. It also included stints working for the late first lady Jacqueline Kennedy Onassis as well as the late Sen. Robert Kennedy. She has also served as a spokesperson for the ever-expanding Kennedy clan and as a liaison among former Kennedy staffers.

Miller first crossed paths with the Kennedys as a youth.

She was just 18 when The Washington Post wrote a story about a bust of the then-commander in chief that she sculpted in art class. The article came to the attention of the president, and that led to a White House invitation. “My principal gave me an excused absence to go … and meet the president on May 3, 1963, at 12:30,” recalls Miller. (Miller, in addition to being called “angel-like” and “unflappable” by colleagues, is also known as “a walking encyclopedia.”) She even got a new handbag for the occasion, big enough to hold her copy of “Profiles in Courage.”

She enrolled at Penn State University in the fall of 1963, but returned to the White House the following summer — several months after the president was slain in Dallas — to work for Jackie Kennedy in the transition office. There she helped organize everything from the “millions and millions of sympathy letters coming in” to the toys that arrived for Caroline and John.

That summer, Miller also met Robert Kennedy at the 1964 Democratic National Convention in Atlantic City. This, in turn, led to a recurring job in his Senate office during college vacations and a full-time gig after graduation.

From Robert Kennedy’s front office in the Dirksen Senate Office Building, she watched thousands of letters and hundreds of visitors come through each day. “He was the fifth Beatle,” she chuckles, adding that during one six-month period the doorstrip to the office had to be replaced because of the excessive foot traffic.

“When you first met her, the two things you noticed about her was: one, she was gorgeous, and the other was how efficient she was. And she’s remained both for 40 years,” says Frank Mankiewicz, who worked with Miller in Robert Kennedy’s Senate office and later served as political director for Democrat George McGovern’s 1972 presidential campaign.

Indeed, at 60, Miller seems to have discovered the secret of eternal youth. She’s dressed in a black suit with a PT 109 boat staff pin from Kennedy’s 1960 West Virginia presidential primary on her left lapel. She is blonde and coiffed, and looks, as her wide circle of admirers agrees, ageless.

“We always said … she must have a portrait in the attic growing old like Dorian Gray, because she’s stayed so beautiful,” says Lenny Donnelly, a former White House aide to President Kennedy and a longtime friend of Miller’s. “She’s such a beautiful person inside and outside.”

After Robert Kennedy’s assassination during the 1968 Democratic presidential primaries, Miller, who had worked on his campaign, was the last person to turn off the lights and lock the door to his Senate suite.

She took a month off to “let [her] nerve endings heal” then got back into the political game, joining Sen. Edward Kennedy’s staff that fall.

Since then, Miller has filled many roles for the senior Senator from Massachusetts, from working the front desk to handling legislation on the Senate floor to serving as assistant press secretary during his 1980 presidential bid. No longer involved in day-to-day press shop activities, Miller for the past decade or so has handled a variety of communications work, special projects and other activities for Kennedy and his family.

Over the years, Miller has been “loaned” to help with Rose Kennedy’s 100th birthday party, and served as the Washington press point person during Jackie Kennedy Onassis’ funeral.

She kept the John F. Kennedy Jr.-Carolyn Bessette wedding plans secret for “a month and a half,” even from other members of the family. And earlier, when a young JFK Jr. made his first major public speech, at the 1988 Democratic National Convention in Atlanta, Ga., she handled his press.

“He called me one morning and said, ‘What am I going to do? Diane Sawyer found where I am and I’ve got seven messages,’” she remembers him saying.

In 1999, she helped with press work surrounding his tragic death, when the plane he was piloting crashed off the Massachusetts coast, also killing his wife and her sister.

“That really knocked the pins out from everybody. For a long time, I still felt I could pick up the phone, and there’d be John on the other end of the phone,” she says.

Miller plans to finish packing up her belongings next week, in time for her official June 30 departure. Her desk bears testament to her devotion to the Kennedys.

Dozens of brown expandable files dealing with subjects ranging from the John F. Kennedy Library to classic Kennedy clippings to Kennedy books line her shelves. Her workspace also features a signed photograph of Whoopi Goldberg, Billy Crystal and Robin Williams pictured during a press event with the Massachusetts Senator; a Wheaties box emblazoned with Edward Kennedy’s face; a Xeroxed photograph of Miller and her mother with President Kennedy; and charcoal sketches of John and Robert Kennedy.

Her own artwork — birthday caricatures she’s given to the Senator over the years — adorn the walls of the bathroom just off Kennedy’s office lobby. It “is the only appropriate venue” for the work, she jokes.

From her perch, Miller keeps an eye on the accuracy of the vast array of books, documentaries and films produced on the Kennedys.

When one episode of the TV show “St. Elsewhere” featured a politician “modeled after” Sen. Edward Kennedy who was assassinated, Miller took it upon herself to write a letter to the producer expressing her concerns that it could “endanger” Kennedy. She later went “toe to toe” with Oliver Stone over his controversial 1991 film, “JFK.”

She’s also held Hollywood accountable in other areas.

When the 1970s NBC drama “The Bold Ones: The Senator” starring Hal Holbrook, now a friend of Miller’s, was abruptly canceled after just one season — “I wrote my first fan letter to the show,” she says — Miller “started a movement to bring it back.” The effort involved everything from circulating a petition on Capitol Hill signed by Barry Goldwater and other Senators and staff to picketing the NBC studios and doing interviews with television critics.

“I never did anything normal,” Miller blithely concedes.

Among her cherished memories is the day that she and Sen. Kennedy returned to his office following a press conference on the passage of the Americans with Disabilities Act to find the reception area crammed with “people in wheelchairs” who burst into applause upon the Senator’s entrance.

Another time she recalls working late one night when Nelson Mandela dropped by to meet with staff. And she proudly remembers the time she was able to help get a house built for the Solomon Island native who saved JFK after the sinking of his PT 109 boat during World War II.

Miller, who describes her relationship with Kennedy as “staff-plus,” will defend her boss to the death — literally.

On one occasion a “very volatile” woman attempted to enter Kennedy’s private office and Miller ended up tackling her — they landed at the foot of Kennedy’s desk. During another encounter, an elderly war veteran, angry over President Jimmy Carter’s amnesty for Vietnam War draft dodgers, arrived in the office to share his concerns, then after thanking Miller for her time, deftly punched her across the jaw with the back of his fist.

“She believes in the same things as most of her liberal colleagues believe in, but she has a charm and grace about her that is sorely lacking in this town,” says conservative commentator Cal Thomas, who admits to “surreptitiously meeting [Miller] on occasion for lunch.”

Her boss, who credits her “ability, dedication, and friendship” with making “an enormous difference for me and for all the members of the Kennedy family,” doesn’t sound like he’s quite ready to let her go.

“We’ll miss the sunshine she brought to the office every day very much, but I know I’ll continue to rely on her in the years ahead for her advice and wise counsel on many vital issues,” Kennedy said in a statement.

“He knows I’m not going to retire and write a book,” Miller says.

Instead, Miller and her husband Bill Wilson, another former adviser to the Kennedys, will “travel a bit.” She may also do some consulting and plans to keep up the activist spirit by joining the board of MOBilizing Mothers (an offshoot of Mothers Opposing Bush or MOB) and volunteering on behalf of animal rescue efforts.

And every year, Miller will come back to speak with interns in Kennedy’s office.

“They say every night when you leave work and you go out and you look up at that big beautiful dome, that if you don’t get goosebumps, then it’s time to leave,” Miller says wistfully. “I’m always going to have goosebumps for this place.”