LUISA DOMIC. By George Dennison. Harper & Row. 178 pp. $14.95.

THIS ECCENTRIC first novel has the characteristics of a fable, a prayer and a commencement address. Narrated in a tone of incantatory solemnity by a poet who is both sensitive and sentimental, it takes as its subject nothing less than the struggle between good and evil. We are presented with a horrifying depiction of a contemporary purgatory and also with an evocative picture of an earthly paradise. The setting is a village in Maine during two golden Indian summer days in 1971, days that suggest Keats' season of mists and mellow fruitfulness. The narrator presides over a little Eden of blazing trees, ripe apples, frisking dogs and romping ponies. Since his studio is in the woods near the home he shares with a loving wife and three exuberant children, he enjoys both solitude and plenitude.

Sustained happiness, though, is not the stuff of serious fiction, and into the idyllic scene comes a character whose grief, brought about by loss, goes beyond despair. Luisa Domic is a soul in torment. Her family's only survivor of the purges that followed the overthrow in Chile of Salvador Allende, she is being driven to Canada by Marshall Berringer, a human-rights activist. It is during their stopover with the narrator's family and another visitor, a world-famous composer, that the central drama unfolds. In a series of domestic scenes that are followed by a documentary postscript, we are exposed both to decency and compassion and to unspeakable moral depravity.

One of George Dennison's earlier books, a 1979 collection of experimental stories called Sweepers and Oilers, features a playwright who is regularly hooted off the stage because his imagery is too crude, too dark. (Dennison is himself a playwright, and all his works deal in one way or another with theatrical illusion.) The unnamed narrator of Luisa Domic need fear no such reprisals since if he errs it is on the side of sweetness and light, his overripe language characterized by a sanctimonious tone that can be cloying. "There now occurred something," he says in his rapt style, "that told me much about my own existence, and that moved me to tears and brought a gasp to my throat." This high-minded man is capable of introducing, in a single paragraph, "hopefulness," "faith," "courage," "pride," "sacrifice," "compassion," "integrity," and "empathy," so that the words finally blur, losing their power. Moreover, he has an annoying tendency habitually to describe the faces of the other characters as "brightening," almost as if they were attached to rheostats.

The adults in the book talk with a ritualized thoughtfulness, and it is hard to believe they inhabit the same planet as the haranguers and interrupters of another recent political novel, William Gaddis' Carpenter's Gothic. When Berringer (as in Berrigan?) finally turns on his host with "a contemptuous sneer," a reader is likely to welcome the gesture, what with everyone brightening, smiling, and behaving generally like candidates for canonization. The three children, who never sulk and don't watch TV, also seem too good to be true, and yet, bright, funny, and spontaneous, they pretty much steal the show. Their father dotes on them, and they are indeed dotable, especially Jacob, 6 -- I would gladly have an entire novel about him. (Dennison's only nonfiction work, The Lives of Children, describes an experiment in humane education on the Lower East Side of Manhattan in the '60s, and here too his portraits of young people are memorable.)

THE NOVEL'S ostensible subjects are political repression and suffering, but Dennison quite clearly intends the book to be, as well, a paean to family life and, I suspect, a father's tribute to his own three children. He also wants to communicate his strong sense of rural values, of traditions, attitudes, and qualities of workmanship that are slowly disappearing. Luisa Domic's most memorable passages, in fact, those in which the language sounds least artificial, are isolated vignettes of a way of life that the author, a self-exiled New Yorker, obviously knows intimately and, again obviously, cherishes.

These epiphanies, which read like pages from a journal, are more convincing than the unlikely discussions of the visiting composer's unlikely music, or even than the anonymous reports of atrocities in Chile. At its best, in fact, Luisa Domic is not a work of fiction so much as a collection of poems or, rather, of lyrical moments of which poems might be made. We are given, for example, eloquent descriptions of swallows swooping around a barn, Canadian geese soaring in formation overhead, a frightened horse that has been clawed by a bear. We meet a native who can tell at a glance what orchards various apples come from and another benign old fellow who knows every acre of the countryside, having delivered milk in the area for more than 60 years.

When a basket is brought into a room, we learn how it was made -- the old-fashioned way, of course:

"The Indian weaver, a neighbor, had found a suitable brown ash tree near the stream below the house, just beyond the millrace that once had fed a little shingle mill. He had come to the house with tools his father had owned before him. The oddly shaped tools were slight and seemed delicate, yet had lasted two lifetimes."

It seems to me that these and similar moments represent the true core of Luisa Domic. It is for them, not for the rhetoric surrounding the larger social issues, that I am glad to add this curious volume to my shelf.