LIVES OF THE TWINS By Rosamond Smith Simon and Schuster. 230 pp. $16.95

"Lives of the Twins" by Rosamond Smith is, in fact, a new novel by Joyce Carol Oates, who, for whatever reason, did not wish to give her right name. Still, her signature is all over it. Oates writes especially good opening paragraphs and this one is no exception. Here it is:

"At this most significant of moments, preparing for bed in their jointly leased apartment on the seventh floor of the handsome new glass-and-poured concrete Greenwood Towers, after a year, or has it been more, of passion, and indecision, and speculation, and hesitation, and -- much, much more: the intricacies of romantic love resist transcription -- at this most delicate and intimate of moments Molly Marks, to her distress, finds herself in the awkward position of having caught her lover Jonathan McEwan in a lie."

That is a very artful paragraph, nicely shaped, liberally decorated with punctuation, the language rhythmic, informative, intriguing, with the key word and its accompanying tingle saved for last. Very artful -- and very self-conscious. And very revealing, too, because the story that follows is really a psychological case study. It is, in fact, more like a "transcription" than a novel, with its three unrealistic, and rather unpleasant, characters; its narrow focus on the workings of their inner selves, with little attention to the outer world in which they move; and its present-tense narrative, still fashionable, apparently, in some literary quarters.

Molly Marks, who is so distressed in the first paragraph, is a kind of Holly Golightly updated to the '80s. Molly is the sort of girl you meet, to borrow a line from songwriter Paul Simon, "at the cinematographer's party." She is young, attractive, vivacious. But she is troubling. She has a longish history of interesting jobs, which only means that she flits endlessly from one thing to another; and a longish history of lovers, ditto.

She is scatterbrained, shallow, thoughtless, self-centered, erratic, her feet unsteadily planted in shifting psychological sands. If you take her home from that party, be prepared. She's a nervous breakdown just waiting to happen at the foot of your bed.

She is, it hardly need be said, the sort of girl who is always "in therapy." Her therapist, Dr. Jonathan McEwan, we are repeatedly given to understand, is a paragon of gentleness and understanding, a credit to his profession. He is also, viewed another way, a spineless and indecisive wimp who, nevertheless, doesn't hesitate to become Molly's lover when the opportunity is blatantly offered. And his own inner life is strange, too. It seems Jonathan has an identical twin brother whom he has never -- through a year of intimacy -- mentioned to Molly.

The twin is named James and he is the exact psychological opposite of Jonathan: rude, selfish, cruel, even vicious. How either one of them manages to continue as a successful, high-priced Manhattan psychiatrist is not made clear.

Molly, upon discovering the existence of James, immediately does the worst possible thing: She makes an appointment, dons the same deliberately sexy outfit in which she first visited Jonathan, sees James, and -- readers will not be at all surprised to learn -- promptly starts a thoroughly meaningless and unhealthy affair with him.

And, of course, it's all downhill from there, in a tale that keeps promising much in the way of menace and kinkiness but doesn't quite get around to delivering.

Among this book's problems is its lack of characters the reader can care about. If you met Molly at a party, you might chat with her briefly over the cheese but then, I think, you'd flee. A few minutes with either Jonathan or James would make me, at least, suddenly recall an urgent meeting elsewhere. And nothing is enhanced by a writing style ("He is a man, Molly thinks, who is thinking -- hard") that frequently magnifies the minimal. Add to that, in the very last line, a classically indecisive and frustrating ending, and you have a very smart and fashionable novel probably best avoided by impatient readers. The reviewer is the author, most recently, of a collection of short stories, "The Bones Wizard."