Outside of business hours (which tended to be very long), the late Giovanni Battista Meneghini was essentially a simple man--a brickmaker who inherited his business from his father, along with the mandate to take care of a sizable family. He worked hard and successfully and became a respected industrialist not only around Verona, where the company began, but elsewhere in Italy.

He was past 50 and still unmarried, expecting to die an obscure bachelor, when lightning struck one evening in June 1947. At the Pedavena Restaurant in Verona (where he lived a Spartan bachelor's life in a single upstairs room), he met an unknown young opera singer named Maria Callas. Before long, they were living together and after about two years they became husband and wife, a condition they maintained for the next decade until Aristotle Onassis swept her off her feet, toyed with her for a while and abandoned her for Jacqueline Kennedy.

Meneghini had, in other words, a strong supporting role in one of the most spectacular life stories of our time. His account of that role should be fascinating and on more than one of these pages it is -- but this happens fitfully, almost in spite of the writer. Meneghini's story, as told to the music critic of Gente, an Italian weekly that corresponds in name at least to our People magazine, is that of a man who seldom understood exactly what was happening to him. He uses the expression repeatedly, with an air of honest puzzlement, whenever his story comes to a point that contradicts his basic theses: that Maria Callas was essentially a simple, warmhearted woman, Italian in spirit despite her unfortunate Greek-American background, and intensely in love with her husband right up to the day she ran off with another man.

"At this point the reader will ask himself," he remarks when the name of Onassis first comes up, " 'But if she was so in love with her husband, why did she leave him to go away with Onassis?' It is a question that has been put to me a thousand times in the years following our separation, and one for which I have never succeeded in finding an answer . . . I have refused to understand, and that is that." The same blank incomprehension is his reaction to the tangled relationship of Callas with her mother: "Maria's comportment in her relations with her family was always a mystery to me. I never really succeeded in fathoming her true feelings . . . Once, when a reporter asked her why she did not send money to her mother, she snapped, 'If she doesn't have any, she can go to work. If she doesn't want to work, she can jump out of the window!' These reports also upset me, but I am certain they did not emanate from the heart."

One can be a successful brickmaker, or a successful negotiator of opera contracts for a brilliant and controversial singer, evidently, without understanding the ambivalence of strong feelings, the lies that people tell themselves (and, of course, others) about their own emotions. For the sake of posterity's understanding of her, Callas should have moved in with a psychologist, not an industrialist, when she arrived in Italy alone, scared and penniless. But psychologists were presumably in short supply, and she settled for what was available.

If he had been a psychologist, Meneghini hardly would have published some of the subliminal information that has slipped into his memoir. His first conversation with Callas, for example, on that fateful night in the restaurant. When the subject of America came up, he felt that he had to butt in and defend his culture: " 'Excuse me,' I said, 'I don't have firsthand knowledge of the United States. It may be an enormous, powerful country, but our tiny things can be worth more than your great things. We have an ancient civilization with art treasures, churches, palaces, and marvelous monuments. Have you seen Venice? No? Well, I am convinced that one old brick, half-decomposed, from the foundations of one of the Venetian palaces is worth more than one of your skyscrapers.' "

There is a certain subliminal poetry in the self-image contained there, the half-decomposed brickmaker identifying himself with a half-decomposed brick. But most of Meneghini's story is much more prosaic. He provides detailed lists of the casts who sang with Callas in the early years in dozens of provincial Italian productions and quotes intensively from the critics with his own exultant or indignant comments appended. Unlike the others who have written about Callas (even her mother for the most important part of her career), Meneghini was there when most of it happened.

But all he can pass on, for the most part, is the contents of old scrapbooks--program listings and press commentaries. This material is relieved from time to time by anecdotes that have the smooth-worn air of often-repeated tales--the kind of story that the teller finally comes to believe whether or not it is true. This material is usually entertaining, and when it varies from the standard version of an anecdote (as often happens), it deserves consideration since the teller, after all, was there. Meneghini is particularly readable on the difficulties placed in the way of his marriage by his family, which wanted a clear title to the inheritance and (by his account) bribed church officials to impose bureaucratic obstacles. He is also useful in retailing backstage gossip from La Scala (where Callas had tremendous problems with management) and other opera houses.

The section for which this book will be bought and read is chiefly the one at the end, about l'affaire Onassis. It is worth reading, though it is more vivid than illuminating. Meneghini's best explanation is simply that it was a "diabolical project" conceived by Onassis after he saw the adulation enjoyed by Callas at a gala in Paris: "If I take that woman for myself, I will impress everyone." The most terrible thing about this explanation is that it seems quite plausible. But even more terrible is his (no doubt, accurate) account of the criticisms she poured on his head as the affair developed: "You act like my jailer . . . You never leave me alone . . . I'm suffocating . . . You're not adventuresome, you don't know languages, your hair is always uncombed, you can't manage to dress smartly."

At last, after nearly 300 pages, the book presents a believable Callas, a private Callas consistent with her documented public behavior, the kind of Callas who could calmly tell her mother to jump out a window. There follows a chapter devoted almost entirely to his last days with Callas, after they left the yacht together and Onassis followed them to Milan -- standard notes on the breakup of a marriage that would be utterly banal to a reader (however agonizing to the parties involved) if it were not for the names on the pages. One sentence leaps out: Meneghini confronts Onassis and shouts, "You invited me on your damned yacht and then you stabbed me in the back. I am putting a curse on you that you never have peace for the rest of your days." Such a scene is probably a standard part of the separation process in the cultures of the three parties involved -- but in this case, one must stop and reflect that the curse worked rather effectively on both Onassis and Callas.

The last words he and Callas spoke to one another were by long-distance phone, after he had finally spoken to the press. "Be careful, Battista," she said, "one day or another I'm going to arrive at Sirmione with a revolver and I'm going to kill you." "Fine," he replied, "and I'll be waiting to machine-gun you down."

"That was the final break: violent and irreparable," he comments. "It seemed impossible to believe that we were so in love only a few weeks ago."

Truly impossible.