Last November a UFO was sighted in Ann Arensberg's backyard in Salisbury, Conn. The 10 or so people who saw it describe a two-tiered, brightly lit craft that flew slowly over the fields, hovered for a while, then zigzagged away. Arensberg's nearest neighbors, a pragmatic couple -- not, as Arensberg says, "interested in UFOs or hocus pocus of any kind" -- reluctantly admitted that they'd witnessed it. But Arensberg, who has devoted no small amount of time to researching, writing about and even courting the paranormal, was in New York at the time.

Arensberg has no doubt that she's being cold-shouldered by the supernatural. Even her dreams are bland and unhaunted. She wishes for nightmares and counts as lucky those whose dreams are "intense and debilitating." Arensberg's third book, Incubus, just out from Knopf, imagines the town of Dry Falls, Maine, possessed by male demons whose nighttime visitations on the local women leave them amnesiac and postcoital. The haunting takes place in 1974, "the last year of the known universe"; at the brink of a millennium, Arensberg writes in the novel's preface, the inhabitants of the dark sense our panic and flock over to "our side" to have their way with the bodies and minds of human beings.

Graveyards, electrical storms and quiet country folk gone suddenly berserk are the bread and butter of another contemporary writer, and Maine's his state. But Arensberg's story bears little resemblance to Stephen King's horror fiction, which she insists she's never read. Nor can it be considered gothic, because the creepiness is truly supernatural in origin: "these creatures are not human and their presence cannot be explained by a medium with an ectoplasm machine." Arensberg hesitantly places her novel in the genre of occult fiction. But this extremely careful, sober book aspires to do more than just raise shivers. The central relationship, between Cora Whitman and her husband, the Episcopal rector of St. Anthony the Hermit, is heavily strained by the hauntings. "Incubus is very much about a marriage and a community. It's about domesticity," Arensberg says.

Since she left her job as an editor (first at Viking, then at Dutton) more than a decade ago for the isolation she believes is sought by novelists in particular, Arensberg's own domestic life has taken a rustic turn. Perennial stalks and leafless rose plants border the house and various outbuildings at Indian Crossing, the home she shares in northwestern Connecticut with her husband, three cats and a small white dog. Behind the house, a yellow winter field extends down to the Housatonic river.

She knows the history of this land and has studied its shape carefully, looking from her windows or up from whatever plant she's crouching over in her garden. Having her hands in the dirt restores her. "Physical labor is a good counter to the life of the imagination and intuition -- you have to turn your mind off, and replenish it from the realm of sensation." She cooks, takes care of her house and writes each day from ten to two at a round table in a converted cow barn, sitting in a chair facing the door. To sit with one's back to the door, she says, is bad feng shui.

Arensberg never intended to be a writer. (In fact, she disagrees with the adage that editors are all repressed writers; they are more often unrealized academics, she says.) Living in Cuba as a child -- her father worked there for the Pittsburgh Plate Glass Company until Castro came to power -- Arensberg attended an English school and got what she imagines to be a 19th-century education. "I never wrote anything. We learned everything by rote only to spew it back during exams." It was not until she went to Concord Academy at the age of 15 that she began to think and write creatively. Even so, when she matriculated to Radcliffe in 1954, she steered clear of the English department, opting instead to study art history.

After working at MoMA for a short time, Arensberg decided to return to school. She left Harvard in 1962 with an M.A. in French literature, moved to New York to become an editor and was married young (a mistake she cautions against).

A Late Start

It was in the quiet left by a separation from her first husband that, with some trepidation, at the age of 39, she initially sat down to write. The first story she wrote was "junk"; she threw it out. The second was "Art History," which appeared in Antaeus and won an O. Henry prize, earning Arensberg the attention of Alice Quinn, then an editor at Knopf. Quinn asked her, if she ever wrote a novel, to send it to Knopf. Five years later Arensberg finished Sister Wolf, the eerie story of the brilliant and aloof young Marit Deym, an heiress who turns her many Massachusetts acres into a wolf sanctuary. The land adjacent to the preserve was once the estate of an eccentric bishop and now is a school for blind children. Among the teachers is a man whose passion, anger and unpredictability rival Marit's. Sister Wolf won the American Book Award in 1981.

In the meantime, Arensberg divorced her first husband and married Richard Grossman, a psychologist and writer. She quit her job as an editor and eventually moved to Connecticut full-time. "If you're going to write," she says, "you should not use up all your intuitive skills on other people's writing. It's better to do something physical, something mechanical, sell gloves at Bloomingdale's, be a turkey-plucker or a bartender. Anything."

After her dark first novel, Arensberg switched gears, publishing Group Sex, a comic portrayal of a kind and spineless editor and her torrid affair with an avant-garde theater director. It was released by Knopf in 1986. What Arensberg remembers of the book's reception was that despite the generally favorable reviews, the New York Times claimed it had no moral center, "whatever that means."

Arensberg stayed with Knopf even after Quinn left for the New Yorker midway through the writing of Group Sex, becoming the charge of Victoria Wilson, who remains her editor. As an insider to publishing, she knows how fortunate she is to have remained with a major house like Knopf, despite the long intervals between books. But after all, Arensberg has yet to produce a book not celebrated for its literary merit. Her thorough and deliberate writing has the clarity and obstinacy of the hard-won.

She calls herself the slowest writer in the world, researching heavily and then writing her novels in pencil on yellow legal pads. Incubus took seven years to complete. The authors she modeled her early work on were those she'd studied as a graduate student, the classic authors of French letters: Stendhal, Radiguet, Flaubert. Their admirable qualities -- compression, spareness, scorn for prodigality -- Arensberg has incorporated into her prose style. She shows no disdain, however, for contemporary writers more prolific than she, expressing great respect for, and a touch of envy of, Stephen King's prodigious output. "I wish I could write like that. Words just pour out." For her own writing career, she feels some anxiety. "I'd like to get a few more books out while I can still hold a pen."

Beckoning Spirits

It is hard to imagine Arensberg too arthritic to grip a pen as she strides down the farm road where she takes her daily exercise, pointing out her neighbor's organic crops and greeting their dogs by name even as she talks with restless excitement about experiences beyond the scope of science and the rational mind. When it begins to rain, she pops her hood up to protect the spiky blonde haircut she hopes will stay intact for the newspaper photographer coming to take her picture at the end of the week. After walking for a couple of miles with the river on one side, pastures of fog and horses on the other, we return to Indian Crossing and settle in the kitchen.

"I'm like the heroine of the story," Arensberg says of her new novel, resting her hands on the table. "I have an enormous number of books about and a great deal of interest in these curious phenomena. On the other hand, I'm extremely skeptical." Arensberg wears three rings: a heavy bloodstone one with her name and her husband's in Chinese characters, a vein-thin blue glass ring, and another whose turquoise pebbles are set in elaborate silver. Decorative objects such as these, and the St. Brigid's Cross above her front door, seem to make subtle petition to forces invisible.

Cora Whitman, the narrator of Incubus, is also a cook and a gardener. Self-contained, courteous and Christian only by association with her husband, she is the last person among Dry Falls's assorted hysterics, loners and imaginative teenagers one would suspect of telling tall tales about encounters with a demon spirit. The novel is, however, Cora's cautiously scientific account of what took place in the spring and summer of 1974, recorded in 1977 for the files at the Center for the Study of Anomalous Phenomena, which she has founded with her husband. "Cora's not credulous, but she comes to accept what's happened," Arensberg says. "She's straddling two worlds. She's earthbound one part of the year and she's in her husband's basement studying parapsychology the other part of the year."

Arensberg lifts an American Spirit, made longer and more elegant by a plastic filter, to her lips. Exhaling, she continues: "People have always seen lights in the sky. People have always had myths of demonic possession. Now these lights in the sky are called spaceships. Since the Middle Ages, there have been myths about sleeping women being raped by incubuses." The myths have evolved, she says, and the rape scenario has developed into the kind of testimony printed in the National Enquirer.

Arensberg believes that there is a tendency to experience the beings of parallel universes -- a tendency that becomes more acute at the millennium's end -- programmed into our collective unconscious. The demons of Incubus, like aliens, give shape and substance to the inhabitants of spiritual territories above and below us.

As someone who feels deprived of the supernatural, the incubus experience is still accessible to her. "Even I -- who've had nothing happen to me-have had sleep paralysis in its most basic form." The limbs go numb, the chest is weighted down, the mind's awake, it's difficult to breathe. Many people, like the characters in Incubus embellish this experience. They claim to smell strange odors (that of cooking meat or flesh), feel the pressure of something like a knee going down on the mattress, encounter the apparition of a pair of eyes of foreign shape. Hence vampires and night hags, incubi and succubi, the beings she's been transfixed and terrified by since she read Dracula as a little girl.

But how much of what people claim to witness is true? "It isn't the literal truth that's interesting" is Arensberg's reply. "What's interesting is where we are going with this. How will the myth develop? Are other universes intersecting with ours? What's next?"

What's next for her, as an author, may be yet another tack. Arensberg has a mystery novel in the works and another novel about which she's rather reticent. This summer she will learn to use a computer and enroll in a Bible as literature course at nearby Simon's Rock. She will persevere in her wooing of the supernatural, though the humiliation of a failed Ouija session with her husband and a copy of Merrill's "The Book of Ephraim" on a rainy night at Gurney's Inn in Montauk still smarts. She will pore over her manual of Tibetan medicine, popular magazines, the White Flower Farm seed catalogue, the p ms of Mary Oliver, the novels of Alice Thomas Ellis, The Oxford Book of Prayer.

It is likely that Arensberg will remain on the fence between skepticism and belief. It is just as easy to imagine her straddling the actual fence that bounds the field where her neighbors saw the UFO, her eyes straining through the twilight for signs of unnatural life, and her fingers crossed in the double hope of warding off and welcoming the creatures from the other side.