Psyching Out a Killer : CALIFORNIA STREET <i> By Donna Levin (Simon & Schuster: $18.95; 290 pp.) </i>

Donna Levin’s lively and engrossing San Francisco murder mystery/love triangle might be described as “a California detective novel.” But it is a sensitive and introspective book, certainly nothing that could be called hard-boiled.

The sleuth is Dr. Joel Abramowitz, a sometimes inept, self-doubting, endearing 33-year-old psychiatrist who mentally toys with the possibilities of every situation he confronts with maddening ambivalence. But it is precisely his ongoing quick-minded neurotic analysis that makes this book so fascinating. We experience the story through Joel’s mind, and he calls on his psychoanalytic training to seek out hidden motivations, posit alternate theories and scenarios of behavior for other characters, and creatively piece together the clues in this puzzle. The subtle subtext is that a mystery writer does exactly the same thing.

“California Street” is an innovative variation on the detective-novel formula, sort of a psychological whydunit in addition to a whodunit. Interestingly enough, such variations are getting to be the rule rather than the exception. From Conan Doyle’s Sherlock Holmes tales to Robert Parker, mysteries have had a large element of the howdunit. But lately, the other interrogatives have dominated. Taking us to Japan or New Mexico, mystery writers such as James Melville (the Inspector Otani series) and Tony Hillerman have pioneered the wheredunit. With settings as disparate as 12th-Century monasteries and 1940s L.A. jazz joints, writers such as Ellis Peters and Walter Mosley take us on whendunit time trips to solve crimes. (I suppose you could also argue that Stephen King and Clive Barker often are writing whatdunits.)

Although readers of P. D. James, Martha Grimes and Dick Francis are howling that these writers are straying away from that cozy, traditional English drawing room down the rocky path of the whydunit, the author who has shaped the psychological mystery novel into an art form is Jonathan Kellerman. In fact, the opening of “California Street” almost reads like a Kellerman novel.

Dr. Abramowitz receives an urgent telephone call asking him to rush to a nearby day-care center: A mentally disturbed woman has a child on the roof. Joel rescues the child and agrees to help the woman as a patient. The scene also introduces us to Margot Harvey, heir to the San Francisco Courier fortune, founder of the Playground Daycare Center and wife of his former college roommate and best friend, Ted Harvey. Joel is in love with Margot, guilty about his relationship with her alcoholic husband, and completely manipulated by her:

“They were a threesome, a dynamic which persisted even when he (Joel) brought other women along. Joel hadn’t ignored the obvious Oedipal implications of that, he’d just--well, ignored them. Ignored, for example, how he didn’t mind going to the theater alone with Margot, if it was something Ted didn’t want to see. After all, he went to games alone with Ted, didn’t he? And sometimes a cigar was just a cigar.”

This trick cigar full of Oedipal surprises blows up in Joel’s face when Margot asks him to run away with her; a new client of his, a beautiful young model, is found dead; Margot disappears but seems to be in contact with the deranged woman from the roof of the day-care center; and Ted admits that he was having an affair with the dead model. Joel races ahead of the police to track down Margot and finds the evidence stacking up against Ted in the murder case. He turns to his girlfriend and fellow therapist Denise for support, which turns out to be complicated because they are sleeping together and she’s in love with him--and he’s not sure whether, perhaps, in some way, he’s in love with her, too.

At first, Joel’s incessant internal dialogue with himself, a running commentary on everything that impinges on his awareness, appears to be a distraction for the reader, a background chatter that keeps us from concentrating on the plot. But, quickly enough, it becomes clear that we’ve just got to sit back and enjoy being in the mind of Dr. Joel Abramowitz, being party to all his anxieties, obsessions,and mental gymnastics. This book is at least as much about Joel’s mind as it is about the external events. Of course, we are also victims of his errors and interpretations, too, which reminds us that there is a novelist telling the story behind the protagonist telling the story.

Levin handles the complicated twists and turns so deftly that the more rapidly the plot unravels, the more involved you become with Joel’s wildly careening life. She sends us roaring into a denouement that Hitchcock would have loved and ties up the numerous loose thematic threads with dramatic flair.

This is an inventive novel that is thought-provoking and fun to read, and Levin, who previously wrote “Extraordinary Means,” is a novelist to keep high on your reading list.