As Time Goes By THE LIFE OF INGRID BERGMAN by Laurence Leamer (Harper & Row: $18.95; 423 pp., illustrated)

Actors are not like other men; actresses are not like other women. While they may also be greatly different one from another, whatever it is that impels them to practice make-believe as a public art makes them kin to each other, and sets them apart from writers and priests, teachers, geologists, cooks and accountants.

Ingrid Bergman was an actress, and the message of Laurence Leamer’s minutely detailed, flatly written and evidently exhaustively researched biography is that being an actress transcended everything else in her life and made a mess of her other roles as wife, mother, lover and friend.

Leamer ends his long biography with an admiring account of the uncomplaining valor with which she endured her terminal contest with cancer, and her supreme effort to finish the miniseries “Golda” despite constant pain and ebbing strength.

He celebrates her passing with rhetorical flourishes: “Ingrid had ascended into myth. The woman who had lived, the woman of bone and blood, of ambition and self-absorption, of courage and cunning, was no more.”

Even the rhetoric is barbed (or balanced, if you will). As it is, the begrudged admiration arrives late. It seems certain that the appeal of Bergman the actress will survive Leamer’s relentlessly demythologizing biography. The Bergman of “Intermezzo,” “Casablanca,” “Gaslight,” “Notorious,” “Autumn Sonata” and “Golda” retains a charisma, like Humphrey Bogart’s, that appears impervious to even the dreariest facts of private life.

Indeed, her 1948 flight from Hollywood, husband and child to join Roberto Rossellini in Italy (a sensation, with which Leamer inevitably commences the biography) left no doubt that she was not a saint, even if she had played Joan of Arc.

But that, Leamer says at some length, was hardly the half of it. He quotes Bergman’s first husband, Dr. Petter (or Peter) Lindstrom, quoting Bergman: “Ingrid said, ‘I’m only interested in two kinds of people, those who can entertain me, and those who can advance my career.”

It is a devastating remark, reflecting on Lindstrom’s part a continuing bitterness toward her. Even her death, Leamer says, “did not free Petter of his regret that years before he had not spoken out to tell the world of an Ingrid Bergman the world did not know.”

The unlovely portrait, and unlovely it is, is of a hard-drinking, hard-smoking, superficial woman whose affairs, as with the photojournalist Robert Capa and several directors, were frequent and not always discreet, who never knew quite what to do with her children and saw relatively little of them, and who lived to act.

While hardly pro-Nazi, she was so indifferent to books and politics that, over Lindstrom’s objections, she went to Berlin in 1938, just after Germany invaded Austria, and made a film, “The Four Companions,” at the famous UFA studio. Ironically, Bergman looks more the victim than the callous adulteress in her affair and then marriage with Rossellini. Their lives together sound as if they were a chaos of too much family and too little money (Rossellini died a million dollars in debt, Leamer reports). In the end he began a conspicuous affair with another woman.

In her own last months, Bergman was alone, living in a small house in Chelsea, although her third husband, Lars Schmidt, by then remarried, remained a helpful friend who managed her financial affairs. (Leamer says her children inherited $1 million apiece.)

The tradition in movie-star biographies is of a gee-whiz love letter woven of borrowings from morgue files. Leamer to his credit has done a full-scale research job, appending notes for each chapter, a long bibliography and a longer list of interviewees. His principal source for Bergman herself was her autobiography, “My Story.” He notes primly that he has drawn on gossip columnists and fan magazines “only as examples of Ingrid’s image.”

While Leamer does not ignore Bergman’s achievements as an actress, his concern is so avidly directed to her private life and persona as to create an imbalance. The open-pore examination, ultimately dispiriting in itself, seems the more exploitative (despite the scholarly appurtenances) because of the lack of a positioning perspective that would have seen Bergman in the context of her times and Hollywood’s times, and captured more of her unique and potent screen appeal.

It’s not that you’re reluctant to know the unpleasant details of her life (although in fact they are depressing rather than titillating in any degree), it’s that she brought unique qualities to American films.

Whatever else is true of them, actors and actresses are blessed in that their best sides survive them longest.