Good vs. Medieval : THE BOOK OF MERCY.<i> By Kathleen Cambor (Farrar, Straus & Giroux: $23, 288 pp.)</i>

Kathleen Cambor’s first novel, “The Book of Mercy,” is about Edmund Mueller, an aging Pittsburgh fireman who becomes dangerously obsessed with alchemy, that medieval science whose goal was to change base metals into gold and discover the elixir of eternal youth. The book is also about Edmund’s disastrous marriage to a flamboyantly manic-depressive woman named Fanny who, after the birth of two children, takes to the road and returns periodically only to confuse and disappoint her injured family.

Then there are the children: Paul, who escapes the home’s close atmosphere of repression and mourning by entering a Dominican monastery; and Anne, the take-charge younger sister who survives a bad-girl adolescence to become a psychiatrist (she specializes in the relationship between infants and mothers) and successfully manage single motherhood. Finally, Cambor’s novel is about Anne’s renewal of contact with the father whose emotional dependence on her (‘Promise you’ll never leave me”) has forced her, in effect, to abandon him.

If all these individual plot lines thicken subtly to express a greater one, it is how the situation of absence caused by Fanny’s defection has basically forged the identities and determined the life events of the other three characters.

According to Anne: “The need for Fanny fueled Edmund, Paul, and me. No matter how we all pretended, missing her was at the center of everything we did. When ordinary living couldn’t satisfy our hunger for her, we all turned to magic, nothing less would do. Alchemy, God, psychiatry.” Specifically, Edmund is attracted to alchemy because of a fantasy he has that Fanny has died and he can bring her back to life.

Cambor deals with such serious, even portentous content through careful organization. Structurally speaking, chapters are titled either “Anne” or “Edmund,” and Anne is the character permitted by the author to speak in the first person; hers is ultimately the informing voice and mind. Analysis, commentary and poetic summation, as in the lines quoted above, is the defining mode of the book. The prose is precise, intelligent and often beautiful. The historical material about alchemy, and the magic spells Edmund uses, Cambor either reproduces or invents, are fascinating and superbly framed. The Pittsburgh setting is also evoked vividly for the reader:

“Steel was Pittsburgh then. . . . The boys [Edmund] went to school with all had fathers who were mill hunks or miners. For school field trips, they went on steel-mill tours; they had a guide who gave a lecture, then showed them grainy photographs of a man posed next to a blast furnace, for scale, for contrast, to show how insignificant man was, compared to fire.”

Detect some literary symbolism here? Alchemy, according to the first real alchemist, the 16th century Paracelsus, whom Cambor quotes, “is the art which makes the impure into the pure through fire.” Of the grown Edmund, we read: “He’d known fire all his life, but he’d known it as an adversary. Would that he’d known better how to calibrate the passions that had burned in his young heart.”

The book lacks a sense of humor, the texture and tonality of characters’ voices scarcely varies from one to another (Paul’s letters home, for example, are positively written by Cambor), and there is a corresponding uniformity to the mood--it is cool (even in descriptions of passions such as Edmund’s) and often heavy with undigested sadness.

Overall, there is too much theme here, too much symbolic striving and poetic working. There is built-in disappointment for the reader--and for more reasons than the fact that Edmund, like many before him, fails to find that quantity called variously “Vital Essence,” “Elixir of Life,” “Philosopher’s Stone” and “Universal Medicine.” The fact is that the story of Edmund-as-alchemist is never truly allowed to run on its own, dramatically. It functions rather as a character trait given by the author to Edmund.

As Edmund is halted by his daughter just when he seems to be approaching the fulfillment of his quest, so is the novel’s emotional progress repeatedly halted by authorial coup: Readers must return, as per decree or curfew, to a chapter called “Anne,” and the rationalist perspective she exemplifies, as opposed to Edmund’s more medieval and artistic worldview. What an amazing author Cambor would become if she broke her attachment to the lapidary prose and elaborate plot construction she’s obviously good at and simply wrote with her poetic energy. The real story here is that of the kernel of passion in the artist’s obsession. Had Cambor gone for depth rather than breadth, what wonders she might have discovered in that seed.

In fairness, however, what is a first novel for, if not to air all the techniques and material one possesses, and clear the way for real feeling and real art? The cruel truth is that those with the greatest talent and skill often must work the hardest. Cambor--student of Donald Barthelme and Rosellen Brown--has a lot of work to do still. If she persists, she could become a novelist who is also an artist.