It's as though Diahann Carroll has spent her life standing on one elegant leg in a paper raft running white-water rapids.

Her recent autobiography ("Diahann!") tells of her continuing struggle to maintain professional success amidst the turbulence of personal stress. And here comes the balancing act again, as she whirls through Washington via Denver, Miami, Boston and the city of "Good Morning America" to promote the book.

"I haven't slept in five days," says the nightclub singer and actress, now best known as the "rhymes-with-witch" goddess Dominique Deveraux on "Dynasty," as she steps away from an on-camera interview at WRC-TV. Around the corner, manager Roy Gerber has his eyes fixed on the clock, anticipating Carroll's flight out of town. This is her last hurrah for today. Then it's back to L.A., with 10 days of rest in Maui, then a nine-day nightclub stint in Vegas, before returning to "Dynasty" this summer.

For Carroll, keeping afloat also means maintaining The Look -- the familiar Barbie-doll beauty (as she herself calls it); the eyebrows permanently raised a la Leslie Caron, the leonine hair framing the delicate, creamy, makeup-layered face. Keep smiling, stay beautiful and work your tail off.

"All I ever wanted to do," she writes, "was sing."

Sing she did, and more. After working as a model for Johnson Publications and winning a contest on "Arthur Godfrey's Talent Scouts" (for which she shed her original name, Carol Diann Johnson), she established herself as a nightclub singer in New York. She moved on to Broadway and a little Hollywood, then to a big TV series -- "Julia" -- in 1968. Her autobiography comes at a high point: At 50, she's more visible than ever in her role as the mean-spirited, jet-hopping Dominique. Which she loves.

Throughout her 30-year entertainment career, Carroll says, she has been offered parts either as a "wonderful, understanding mother who is the epitome of an upstanding citizen" (on "Julia," she played a goody-goody nurse) or as a "total hooker -- a woman with no morals." But while Dominique "is slightly bitchy, certainly manipulative -- she's certainly interested in power," she also "has a child she loves very much. She has had relationships that have involved marriage . . . and that have not involved marriage. She produced a child out of wedlock. But she's an important part of the reality of today."

Carroll's even asking the producers to make Dominique "more nasty, even more corrupt . . . I think it's what the audience wants to see. I hear that constantly [from fans]: 'Are you going to get Alexis, Diahann?' And Joan Collins and I enjoy it and we look forward to it."

Speaking of soapy drama, Carroll's autobiography is a laundromat full: a passionate romance with Sidney Poitier, beatings from many men in her life, one marriage that ended with violent death and another that ended almost as soon as it began, an affair with David Frost, and estrangement from her father. She was sexually attracted, she writes, "to the negative and the unacceptable . . . every sexual encounter practically had to have the overtones of a rape scene."

"I felt I wanted to talk about myself," says Carroll. "I wanted to see if the book represented something I could report honestly and if it might offer some information particularly to young women . . . That's why I decided to go into areas of my life that are terribly personal -- the battered woman . . . my accepting the beatings at a time when I was enjoying the greatest success of my life" -- "Julia."

*She writes about the inevitable racial problems. When Carroll was a child, a white doctor molested her, but there was nothing her black parents could do about it. She had to watch as a couple of North Carolina policemen verbally abused her father, stripping him of his dignity because he was driving a shiny Chrysler. Then there was the call from Bell Telephone Hour saying, "We can't use Carol because she's married to a white man."

Some of the most striking passages deal with Poitier -- an egotistical, insincere man, according to Carroll, who swept her off her feet when both were married to others. He moved, she writes, "like an animal, an incredibly beautiful, self-confident, jet-black man with the satin skin of a panther."

It was a nine-year romance of almost constant frustration, as the couple waited for Carroll to divorce her first husband, casting director Monte Kay, and for Poitier to divorce his wife. Threatened by her success, Carroll writes, Poitier was alternately romantic and psychologically abusive toward her, and ultimately reneged on his promise to divorce his wife. Why this public attack? "Sidney wrote a book a few years ago and included a chapter about our relationship," she says. "I don't feel as though I opened this. I did not initiate this examination of our relationship in public."

Robert DeLeon was the young managing editor of Ebony magazine with a "brilliant mind" who, after marrying Carroll, used her name to run up insurmountable debts, beat her, was insanely jealous of even her girlfriends and subsequently drove his car off a California ravine to his death. "Whatever the problems that led to the death started years before I came into his life," she says, "probably in his childhood. But I miss him . . . Death is so final, there is no exchange ever again, and that always makes me very sad."

In the early '70s, Carroll's betrothal to David Frost made tabloid headlines all over the world. But she broke off the engagement suddenly -- "I was not ready to be the kind of partner that David needed" -- and immediately married a Las Vegas businessman, Freddie Glusman. His neck was festooned with gold chains and he wore shirts, Carroll writes, that made him "look like the lead singer in a rhumba band." She was "drawn to Freddie's roughness and lack of sophistication at the same time as they repelled me." But when he beat her one night because she wasn't amorous enough at 3 a.m., she divorced him.

Carroll's parents raised her to be "different" from the other kids in Harlem. They were reluctant to see her singing in nightclubs, preferring that she go to college, but though she enrolled at New York University, success came before she could get a degree. They also disapproved of her relationship with Poitier and resolved to give him a talking-to -- but when the celebrity showed up at their home, they were too awed to do so.

In the early '70s, Carroll's father left her mother, and there has been limited communication between father and daughter ever since. "There was a period of a year where I had no idea where my father was," says Carroll, who hopes for a reconciliation, "and I could only reach him through a Post Office box. He used to tell me, 'You always turn to me when there's trouble' . . . There was no way to be prepared for this man to feel that he had to withdraw from me as well as my sister to this extent."

As for her own daughter (Suzanne, 26), Carroll says, the main difficulty "has had to do with travel, absence, the absent mother . . . She was primarily raised on the telephone. Many times I was so present on the telephone, I was an intrusion, more so than the parents who were home every evening . . . (NEW-LINE)I was operating out of a kind of guilt, a need to call, to keep constant tabs on every moment."

Highlights of the career she juggled with motherhood have included "No Strings" (for which she won a Tony) and "Agnes of God" on Broadway, as well as her film work in "Paris Blues" and "Claudine" (for which she was nominated for an Oscar.

The big success, before "Dynasty," was "Julia," though the role got mixed reviews. Carroll's character was too innocuous, critics said, too homogenous; there was no relationship with a black man; a nurse with Julia's income could not possibly afford the clothes she wore.

It's a subject Carroll has been asked about for years.

" 'Julia' was a half-hour sitcom," she says, taking a deep breath. "I don't know of any half-hour sitcom, certainly at the time 'Julia' was on, that was representative of any real slice of life of any group -- Irish, French, Lebanese . . .

"I think I served a positive purpose," she continues. "I think there were millions who had never seen middle-class blacks before. While [the show] was light and certainly fluffy, the relationship between the mother and the son was important. The relationship of the black woman in the work place was important."

As for the clothing criticism, Carroll doesn't want to hear any more about it. Look at "That Girl," she says. "[Marlo Thomas] was an unemployed actress. Her father owned a diner or something in Upstate New York. She wore designer clothes. No one has ever questioned that."

But "Julia" is far behind her now. These days, she has to contend with charges that she's too nasty, not too nice. "The black community can be very demanding to its artists. It does not want a character that doesn't depict us at our best. That can be very limiting . . . " She understands the desire "to depict blacks as often as possible in a very positive light. But we have to outgrow that. Black artists have to be more creative and more human. We must accept that we have our frailties: Our dope pushers and our ministers, our politicians and our corrupt politicians, and our wonderful good mothers . . . I just think we have to cover the whole spectrum."

* Carroll explains that she's "been up the hill and down several times," but has come to an age where she is at "a very nice leveling-off place." She is presently exploring that place with singer Vic Damone. "I try not to talk about him a great deal. He's a fine human being . . . It's a pleasure to be in his company."

Hers is the story, she says, of a woman "who started in the '50s and is still alive and kicking in the '80s, and the experiences that have catapulted her to the top and thrown her to the bottom." The moral? "We are entitled as females to pursue [careers], and we should recognize that we're going to need not only partners who are supportive," but who "are proud of our endeavors."

And with that Diahann Carroll stands up on her Minnie Mouse white pumps, stretches those elegant legs, and goes into her balancing act once again.