Susan Cheever seems to know just how certain things are put together. She knows about the inner workings of sofa upholstery, for example, down to every small stitch in the fabric and every coil in the springs. She knows what goes into putting together a cover story for a national news magazine -- along with the correspondents' reports are the late nights, the office politics, the endless cups of vending machine coffee. And, somehow, she even knows just how an elephant cage is constructed, complete with fancy iron grillwork and heating ducts.

In her third novel, "The Cage," Cheever details all of these things precisely and well. But her real point is to show us a different sort of intrastructure, perhaps the most complicated and fragile one of all. What Cheever digs up for us to examine in this book are the bare bones of a marriage.

The couple in question are Billy and Julia Bristol. They are in their late forties, rather well off, living in a suburb of New York. Billy is a senior editor on an unnamed news magazine. Julia keeps house in the suburbs and worries that Billy is having an affair in the city. The couple's only child, a daughter named Cece, is in California living with a man her parents are not certain they approve of. In the summertime, the Bristols live at Northwood, their huge, gothic-novel-style estate in New Hampshire. The place was passed down to Julia by her father, the rich and handsome Charley North.

North was the sort of man to inspire dreams -- especially Julia's dreams. She remembers that he always smelled of "bourbon and good tobacco and Irish tweed." He always called Julia "my little princess." The real problem is, now that Charley North is dead, Julia is nobody's princess. She spends her days awash in self-pity, remembering the way things used to be and longing for summer when she can return to Northwood. "Northwood with its great turreted house and big old barn and rolling pastures down to the lake." Northwood with its lavish gardens and its fancy cages for the monkeys and lions and other animals that once made up Charley North's private menagerie. Now, the flowers have gone to seed. The animal cages stand empty. But none of this really matters to Julia. "Northwood's shabby magnificence and its empty spaces represented a final remnant of her father's kind of life -- and the proof of her own continuing specialness."

But, this particular summer, Northwood does not fulfill its promise to Julia. From the very start of the vacation, things do not bode well. The house is in terrible repair. There are mouse skeletons in the bathtub, bat droppings on the floors. The rooms seem darker and more ghostly than ever. Deer get into the vegetable garden and trample the tiny, perfect seedlings that Julia is nurturing. A letter from Cece brings distressing news. And, worst of all, when Billy arrives, a few days after Julia, he is lost in thought about the big cover story he has just finished writing for the magazine. His secretary calls from New York several times a day. Between phone calls, Billy spends his time out in the old elephant cage, cheerfully hammering and sawing boards to mend a ruined wall of the structure.

As the tensions build for Julia, Cheever skillfully builds the suspense for us as well. Things finally snap as we know they must and the novel's ending is chilling and effective.

Unfortunately, however, not everything in this book works quite as well as its final scenes. "The Cage" is a relatively short novel -- 180 pages -- yet in places it drags as ponderously as an elephant pacing back and forth in its cage. The major problem lies in the character of Julia. In order to make the book's ending plausible, Cheever had to give Julia Bristol a generous dose of helpless narcissism. But, along the way, Julia seems to have been given an overdose. This is a woman who gardens in a cashmere sweater and spends her spare time examining her face for new wrinkles. Julia appears to have no close friends, no interests beyond her self-appointed domestic tasks. She calls her husband at work to whine about her life. When her marriage is in extreme crisis, she waxes her kitchen floor. When she's miffed at Billy she decides to bake him a cake from a mix instead of from scratch. Julia Bristol might just as well be cut out from a package of cake mix herself. She is a high-toned, fine-boned version of Betty Crocker, except that Betty would probably show more spunk. What all this means is that the chapters of this book that are presented from Julia's viewpoint are as flimsy and irritating as she is. It's difficult for us to believe in her or understand her relationship to Billy Bristol.

There are other, smaller problems with the novel as well, including some awkward shifts in the narrative and a strange kind of travelogue voice that intrudes every so often to inform us about certain buildings and restaurants in New York. But there are fine moments too -- images which stay with us, such as the picture of a run-down New Hampshire town getting ready each year for the tourists who never arrive; the retirement party for a magazine editor who does not want to leave; and the faint, pink dawn breaking at Northwood in those final haunting scenes. These are the moments that show us what we may look forward to from Susan Cheever next time around -- a precision of language and detail, a tension as strong as the sofa spring that's just about to snap.