TWO YEARS AGO in the midst of rehearsals for the Kennedy Center revival of Ghosts -- a production that was not shaping up well and would, in fact, encounter stiff critical resistance when it opened -- Norwegian actress Liv Ullmann admitted, "If I could make a living out of writing, I think I would do that. I think my life could have more impact if I were not pretending so much as I have in the past."

By "pretending," of course, Ullmann meant acting -- an endeavor that has won her world- wide renown. But there was -- and is -- more to her remark, when you consider the last line of Choices, Ullmann's second volume of autobiography (after the best-selling Changing). At the end of this slender, probing book, Ullmann writes of herself, "There is a woman in Norway who tries to understand."

Indeed, a fundamental difference between this book and most celebrity autobiographies, which attempt to pass on the accumulated wisdom of a lifetime, is that Ullmann, at 45, is still groping for knowledge of herself and the world she lives in. She doesn't "pretend" to have any answers. She has come to realize that her own ambition, the male mentors (Ingmar Bergman, chief among them) who helped shape her career, and then fame itself all contributed to insulate her from her deepest feelings. While she has had love affairs, she cannot claim to understand love's workings. A mother, she contemplates the growing pains of her teen-age daughter Linn with a mixture of compassion and bewilderment.

She reflects on the "choices" she has made and wonders if she isn't as much defined by those she failed to make. She gazes at herself in the mirror. What looks back is one of the international cinema's most expressive faces, but still she writes, "I want to experience the way I was then, when I was very young -- the sounds and the fragrances, the faces of my childhood. I am looking for the child in myself. The lost innocence. The purity and the freedom. Truth. But I find that everything that was is gone forever."

And she senses one of the great paradoxes of acting: A profession that presumably strikes at the very heart of human beings, illuminating the darkness, it may simply be a glorious charade, a substitution for the real business of living. "Roles do not change me; life does," she notes. "I do not want to arrive at the end of life and then be asked what I made of it and have to answer: 'I acted.' I want to be able to say: 'I loved and I was mystified by it. It was a joy sometimes, and I knew grief.'"

Not all that surprisingly, one of the early titles Ullmann contemplated for this volume was "Tides." Reared by the sea, she has always been fascinated by its infinite variety. In its flux, she perceives an image for her own life, and she suspects that its immutable depths contain eternal secrets like those she is trying to fathom within her own self.

Choices covers roughly a four-year period in Ullmann's life beginning in 1979, when she was starring on Broadway in Richard Rodgers' last musical, I Remember Mama, and getting booed by a man who would enter the theater without fail every Thursday just in time for her curtain call. It details the flowering, and then the painful dissolution, of her affair with a Czechoslovakian she calls only Abel, who came to interview her for a television program and stayed on. She confesses that she agreed to appear in Ghosts, thinking that it was the English translation of When We Dead Awaken, a play she would have vastly preferred. When she discovered her error, she was too embarrassed to back out, although from her chronicle of the first 12 days of rehearsals, she probably should have. ("The older one gets in this profession," she notes crisply, "the more people there are with whom one would never work with again.") She takes an African safari with Linn and directs her first film, a 15-minute short called Parting, in Canada.

The bulk of Choices, however, is devoted to her world-wide travels, as an international spokesperson for UNICEF and IRC (the International Rescue Committee). If one event can be said to have changed the course of Ullmann's life, it occurred in February 1980, when she, along with such notables as Elie Weisel, Joan Baez, Winston Churchill III and Alexander Ginzberg, flew to Thailand, and then marched to the border of Cambodia with medical supplies and personnel in order to focus attention on the plight of the Cambodian refugees. Since then, Ullmann has undertaken countless trips to the hell holes of the planet to observe human wretchedness first-hand and -- because even wretchedness cannot entirely snuff out the nobiliy of the species -- human gallantry, as well. In Haiti, she sees hunger everywhere and a man, whose very face is being devoured by maggots. But in a poverty- stricken village in Bangladesh, a 9-year-old "elf of a girl with long black hair flying all around her face and shoulders" takes her by the hand and says, "I want to show you everything that is wonderful in my life. I want to show you my home and my family and everything that grows."

Ullmann describes victims of famine, war, earthquake and floods with an affecting lack of bathos. But it is not just the staggering misery that haunts her. She, who has been confronted with a plethora of choices in her life, is profoundly disturbed by the plight of those, who have no choice at all -- not even the choice of living. Struggling to find a kinship with them, she writes, "The woman who wants to give her child away to save it from starvation is me. If I do not acknowledge her in the living span of time we share of earth, how can I expect to be acknowledged myself?"

Even as she is speaking out, she recognizes that her humanitarianism is fragile. After being exposed to the horrors of Bangladesh, she finds herself on the plane ride home complaining to the stewardess about the taste of chlorine in the coffee. She turns down acting jobs, claiming she has no motivation for performing. But privately she wonders if it isn't because acting might all too easily anesthetize her newly awakened social conscience. "The truth is I am afraid to lose touch with the sense of reality and compassion that people I might never see again have awakened in me."

It is this attempt to be ruthlessly self-honest that gives Choices its distinction and compensates for some real limitations. There is no concerted narrative and Ullmann often seems to be recording her assorted thoughts and vignettes as if in a bedside journal. In her desire to get to the essence of things, she frequently glosses over names and facts. She casts some of her confrontations with Abel in the form of a screenplay -- complete with stage directions -- an approach that seems coy at best. And when she allows herself to wax poetic, her prose is not always the most felicitous.

Still, there is wisdom in this book -- the hesitant wisdom of a woman in a state of evolution. Once Ullmann found truth in the controlled environment of the theater and films. Now she is looking for it in the very chaos of life. The answers, she makes it clear, come harder in life.