BOOK REVIEW / NOVEL : When People Grow Strong Through the Death of Another : THE GOOD HUSBAND <i> by Gail Godwin</i> ; Ballantine $22.95, 468 pages

Gail Godwin’s new novel has a largish theme--the redemptive effect produced in others by the slow, valiant dying of an outsized protagonist--but as with some restaurants, the side dishes come off better than the main course.

As Magda Danvers, a charismatic professor and author of a hugely successful book on literary visionaries, struggles feistily with terminal cancer, three others find their lives changing. One is Francis Lake, who was smitten with the older Magda when she came to talk at his seminary 25 years earlier. He gave up his priestly vocation to marry her, and has comforted and waited on her ever since. Another is Alice Henry, a young woman whose own hold on life has been made tenuous by the deaths, in her adolescence, of her parents and a beloved brother, of the aunt who then raised her and, as the novel begins, of her stillborn baby. The third is Alice’s mismatched husband, Hugo, a talented, blocked novelist.

Godwin writes graphically yet sensitively of Magda’s week-by-week decline from a strong and still-beautiful woman vivaciously receiving her visitors, to the shrunken, incontinent hallucinating figure of the last days. She writes of a spirit that remains vital even when it wanders. The “Great Uncouth,” Magda names her cancer. “From its point of view I’m the impediment.” She has been a good student all her life. “Now I must see what I can learn from my final teacher,” she says.

Her suffering and deterioration are Francis’ ordeal, but their very awfulness offers him a healing relief, along with grief, when she dies. His serenity caring for her and accepting the prospect of her loss--Godwin’s “good husband” plays the role traditional to an accomplished and devoted wife--brings Alice out of her long-frozen trauma. Her thaw will end her marriage, but in a way that allows both her and Hugo to move on. The dying Magda prophesies the end. You are not married, she tells Alice and Hugo when she sees them together; and she bequeaths Francis to Alice, a bequest that seems likely to take effect.

Much of this is effective, though a touch stagy. But a literary death is the equivalent of the minus sign in mathematics. It has no real dimension of its own; its power depends on the value of the integer to which it is applied. And though Magda brings off some striking gestures and phrases, Godwin has not managed to make her of much real interest.

We are told of the splendor of a figure whose physical and stylistic flamboyance suggests an American Germaine Greer, and also of her internal hesitancies and failures. We see the other characters impressed by the splendor. But we don’t see the splendor itself or, rather, we don’t see the person to whom it attaches. She is an adjective with the noun missing; a fictional essence with only a slight fictional existence.

The same is true of two of the other three. Alice was once a brilliant book editor. Her suggestions for a flawed novel of Hugo’s had turned it into a marvel. (Godwin’s narrative train is rather punctual.) He marries her for it but, after the stillbirth, she can’t stand him. Her not standing him takes up so much of her presence in Godwin’s book that there is little left to interest us once she starts succumbing to Francis.

Francis is a figure of saintly humility. He is not hypocritical or smug and Godwin gets us to accept, even to like him. But her treatment is so tastefully recessive that until the end, when he colors slightly, it is hard to feel that he is quite there. This is particularly true, of course, since the object of his veneration and service is so largely adjectival.

Hugo is less special but, oddly enough, more satisfactory. He is the self-centered, insecure artist but there is an innocence to his need for attention and esteem that makes him human, and that makes the book come to life when he appears. Alice can’t believe he truly sorrows for the dead baby. We know he does; and we know it not from anything he says but simply because he keeps remembering the tiny widow’s peak he glimpsed as she was bundled away.

Hugo furnishes most of the small rebellions and asperities that enliven the book’s cloudily embodied larger designs--notably, its long mediocre flashbacks that tell us why he and Alice have reached opposite ends of their marriage and are still diverging. Perhaps we will not particularly want to know. We may prefer to see short, plump Hugo steaming at a tall, skinny rival novelist who slouches above a cafe table and protrudes his knees and elbows as if asserting moral and artistic advantages: “He gave the impression of positively glorying in his own arrangement of bones.”