THE POTATO BARON by John Thorndike, New York: Villard Books, 320 pp., $15.95
AUSTIN AND FAY POOLER have been married for 20 years. They still love each other. They still find each other sexually attractive. They have a college-age daughter and an eight-year-old son.
Austin believes in his work: growing potatoes on his family farm in northern Maine.
Fay believes in Austin: ``I like a man who's passionate about his work,'' she teasingly but truthfully tells a pair of bankers she meets at a party, who seem surprised that a Harvard graduate like Austin should bury himself in farming and that an elegant, college-educated woman like Fay should throw herself away on a farmer.
The Poolers have never been the sort of couple to fight over who takes out the trash. Glancing at a women's magazine filled with articles like ``Let Him Wash the Dishes - He'll Love You for It in the End,'' Austin reflects that he and Fay have shared the chore of dishwashing for 20 years without making a fuss over it.
Austin's belief in his marriage is linked with his belief in the value of his life on the land. He hates the urban sprawl of the entire Eastern seaboard south of Maine, and attributes most of the world's problems to homelessness, lack of land.
One day, suddenly, but not entirely without warning, Fay takes eight-year-old Blake and leaves the farm. Austin is faced with having to choose between his two most valued (and heretofore complementary) relationships: with his wife and with his land.
For the past 10 years, as we now learn, Fay has been trying to persuade Austin to give up the farm and move somewhere less cold and isolated. She has finally done the only thing she feels will get through to her husband, whom she says she still loves.
Her devastated husband is determined to get her back. His pursuit takes him to Mexico's Yucat'an Peninsula, to Florida, and points west, with trips back home to check on his potato crop. Fay is still willing to meet and talk with him, but she has made up her mind not to go back to life on the farm. Having devoted herself to his way of life for so long, she's ready for a change.
Austin is forced to concede the justice of her claim, but it's rather abstract justice, pitting his very real farm against her nebulous desire to live somewhere else.
This well-written novel (the author's second) asks us to accept the premise that a happily married woman will walk out on her husband because she's tired of living on a potato farm - or, in more general terms, because for once in her married life, she wants to lead rather than follow.
Some novelists would use this occasion to probe beneath the seemingly happy surface of the marriage to uncover deep discords that may have led to the break. Thorndike concentrates instead on showing how husband and wife react to the new situation.
At times, the novelist seems to be turning the story into a kind of sexual odyssey, as the separated husband and wife set out on their divergent - but sometimes interlinked - adventures.
But the real purpose of these interludes soon becomes evident. The characters and the nature of their marriage are being revealed and defined through these incidents.
Although both Fay and Austin sometimes succumb to temptation, both turn out to be capable of ``just saying no.'' Mature and realistic even in the throes of what might have been for each a second adolescence, both worry about AIDS and take precautions on those occasions when they don't say no.
In the course of pursuing Fay, Austin discovers that rootedness in a relationship is finally more important than rootedness in land, and both he and Fay demonstrate, in the course of their various adventures, that strong characters with a secure sense of their identity can remain true to themselves - and each other - amid the flux of changing circumstances.