IT'S A PARTICULARLY fine morning in New York and Lillian Hellman is wearing a polka-dot silk dress, a spring dress -- ladylike. If all goes well with our interview and an annoying doctor's appointment, she'll be going out to lunch.

Now she sits in the study of her apartment -- a plain back room with a comfortable couch, big desk, typewriter table, a wall of books. It is a workroom, a thoroughly used, writer's room. On the desk a sheet of paper is propped up, with the telephone number of an old friend written in giant numbers. A half-written page in the typewriter is in huge block letters.

She sees my form coming towards her and the form of the tall, vibrant young woman who helps out in the house. Then she sees me through the thick glasses that she hates and which the doctors now say are wrong for her. The glasses change the famous face, the face that has always photographed as large, scored by her past, still ready for anything, into the small face of a more delicate woman, forced to be cautious.

Settled on the couch, we talk about her summer plans to go to Martha's Vineyard. Again this year they must be delayed, because of the doctors second-guessing about her eyes. But she is already transported in her mind to her garden, to a good day on the fishing boat.

There is a moment of honest depression and then we talk on until Lillian Hellman comes to a story about a pretentious lady we've both met -- an innocent, hilarious story. Then energy is all there. The voice strong, genuinely theatrical, and a deep, somewhat raucous laugh undercuts any impression she's given me this morning, with the nice hairdo and the proper dress, of a genteel Park Avenue matron.

Attending to business, we turn on the tape recorder that sits between us. I've come to talk to Lillian Hellman about her new book, Maybe (Little, Brown, $7.95), a remarkable, intricate, fresh story. Because of our general good mood the first question I ask is, "Did you find it pleasurable to write?"

"Yes," she says, "I did. I don't always find it pleasurable. I don't know whether it was because, as you know from reading the book, I was out to try a theory, and it was new for me, and there was a great deal of fun and pleasure in fiddling with it."

Maybe is about people and events in our lives that are peripheral, about incidents and characters we don't keep track of, about the difficulty of validating so much of our experience. Theoretical indeed, but the idea is given to us dramatically in the story of Sarah Cameron, a mysterious, offbeat beauty Hellman knew over many years. It is a fascinating narrative, carefully structured, intentionally disjointed, an accumulation of evidence about a woman whose role in Lillian Hellman's life seemed completely unimportant.

I suggest that the problems she faced in writing Maybe are not unlike some of the problems that must have come up in writing her memoirs -- An Unfinished Woman, Pentimento, Scoundrel Time -- questions of sorting stories out from the whole of life and the responsiblility of the present to the past.

"In the other books," Hellman's voice is deliberate, measured, "I was out to say 'I do remember' as accurately as I can remember, as factually as I know it. This time, I was trying to say a great part of everybody's life has been the passing people who haven't even mattered enough to have been observed very carefully, or who have themselves misled you. Perhaps you have misled yourself or not paid enough attention or not cared enough. Perhaps I wasn't at the right age, or even if I had been, I wouldn't have been capable of seeing -- maybe they were playing games, maybe they weren't maybe you were important to them -- who knows. But nothing is verifiable here, either to me or probably to them.

"This is quite different than this theory I have about memoirs. I think memoirs ought to come as close to the truth as one can possibly get."

But passing experience, if I've read correctly, the experience comprehended in Maybe -- Sarah Cameron's adventures -- this background fabric has to be dealt with too. We really have to be responsible even to this; it's not trivial or dismissible.

"On no, no -- I wanted to say why I had, lying idly in bed, chosen this woman I hadn't thought about in many years, and I'd obviously chosen her because it brought back certain other incidents of my life that had mattered to me so much."

We talk then about the fact that a great deal of our lives depends on odd connections we can't figure out, on happenstance, and that we seem to remember and shape the narrative of important events. But we also live in shadows, much is forgotten. I recall a line from Borges: "Our minds are porous with forgetfulness." It is all very strange. Nothing can be taken for granted. The woman named Sarah, now a central figure in her book, Hellman last saw or thought she saw in a San Francisco hotel and forgot about it in 20 minutes. She hopes that Maybe says that life is a queer business: "I don't know, maybe you do, but I don't know why 75 percent of my life happened or how it happened or why I was where I was. I never believed the people who had the reasons for what they did and how they did it -- not even when somebody said they married for love or money. I always suspected those clear-cut reasons."

"How are we to read the book, then?" I ask. "Lillian Hellman appears in it. Sarah was real, her husband, her son are real, but you must construct their story from pieces as though they were strips left on a cutting room floor, a story you thought you had edited out of your life. Doesn't Maybe tend to be fictional?"

"Not fictional," Hellman says readily. "Whatever I say in the book that I think I saw is the truth. As I saw it. That doesn't mean it's true. And wherever I said I didn't remember or wasn't listening -- for example when Sarah told me the story of the gangster she was involved with, I wasn't listening or was quite tight, so I'm not at all sure if I ever got it straight. I got certain people straight. I remember purple and the old lady, and I'm certain she was making up about one-half of what she told me about the gangster."

I worry the point that Sarah Cameron becomes a character in the book, that Lillian Hellman does, too -- is a sort of persona - that Maybe tends toward fiction and Hellman claims she doesn't know any more about that: "I don't know -- well I know -- that's not true," she says. "For three or four years I've been toying around with the idea -- how do you, instead of doing a memoir, straight memoir in which I think you should try as hard as you possibly can to tell the exact truth, as exact as you can come to this truth which, of course, is not exact ever -- how can you do a certain kind of memoir which says I do not know the truth, but this is the tale as I knew the tale. So it's part fiction, of course, part guess work, part invention."

Doesn't it seem reckless, I say, to have written Maybe, to go on a new theory late in the game, reckless in the way artists should be, a nonprofessionalism Marianne Moore admired.

"Yes, I don't think I thought of the word reckless. I thought I don't know what I'm doing, but I'm going to try it anyway. I'm in deep waters now. Maybe I can swim out. Maybe I can't."

At the end of the book there is a scene in which Lillian Hellman is lost swimming in familiar waters near her house. "But I couldn't see the shore," she writes. "the word frightened is not the word. I am not frightened in water. Something else was happening to me: I was collapsing in a way that had never happened before." She is furious at the circumstantial, her failing eyesight, but finds her way home to bed. She writes of a "montumental despair" and sends a telegram to Sarah Cameron's husband, a man who had tidied up his life so that there are no more questions, only the black wall of answers, and the telegram proclaims to him in bold type, like that enormous print on Hellman's typewriter, that she must keep making distinctions.

"I fooled with that ending a great deal. I rewrote it about four or five times. I couldn't get it right. I couldn't seem to say what I wanted to say and I'm not sure I did anyway."

The story Maybe exists as a book, has that placement now, and Hellman says she is going to try it again. It's the subject that fascinates her -- what seemed important, directly in sight, and what seemed unimportant, peripheral vision. "I don't seem to -- taking things as fiction -- be able to put myself out of the way. I don't have the nerve to try real fiction." It is not fake modesty but an assured assessment of her later career, her career in autobigraphy after the years of writing for the theater.

We talk about her reading -- it has been almost impossible for the past three years. It is tiring, painful, but she's terribly funny describing books she's bought on tape and the hopeless frustration of trying to find a favorite passage in Thoreau in hours of badly enunciated prose droning at her. She goes back to Sarah Cameron. Why did that woman rise to the surface of her mind when she was in despair -- a wandering woman, a woman who seemed to just accept whatever came her way and never cared much about anything? There are more tales about such lives, a displacement of her own story, maybe.

This is not Lillian Hellman, public figure, the Hollywood Hellman, the Hellman of Broadway success, or Hellman in the illustrious photos -- with Hammett, with Dorothy Parker, Sid Perelman, before the House Un-American Activities Committee. This is a frail, small woman, smoking, laughing, talking well, thinking well, ready to try another story, another go-round with the doctors and the new lenses. As I write up the interview I am reminded of a line from George Eliot: "Men, like planets, have both a visible and an invisible history."