PERHAPS THE BEST NEWS about Heading West is that it should liberate Doris Betts from the relative obscurity in which she has labored for most of her career. The novel, her fourth, has been chosen by the Book-of-the-Month Club as a dual main selection, which assures it a substantial readership. Those coming to her work for the first time will find that she writes clear, vivid prose, creates distinct and interesting characters, and is a master at conveying the nuances of psychological conflict; she is a serious writer whose books are unfailingly intelligent and readable.

But for those who have followed Betts' work over the years, Heading West is not unalloyed good news. It may be her "breakthrough" book in a commercial sense, but it is not an artistic breakthrough. She is one of the best writers of fiction in the country, and a very important figure among those Southern writers who have come to prominence since the '60s, but she has yet to demonstrate a firm grasp on the structural complexities of the novel; in Heading West, as in her previous novels, she reveals herself to be a short-story writer who is uncomfortable going long distance.

In fact she is a writer with two careers, or two personalities. As a writer of short stories she is in the tradition of Flannery O'Connor, though very much herself; these stories appear in literary magazines, mainly Southern ones, and have earned her a reputation as a craftsman and stylist worthy of comparison with O'Connor, Peter Taylor, Eudora Welty and other American masters of short fiction. But as a novelist she reaches for a larger audience; her novels are not exactly "commercial," inasmuch as that term has acquired negative overtones that do not apply to any of her work, but they do tend to be overlong and overplotted.

Heading West is actually two novels. The first, which ends on page 215, is quite brilliant; it is the story of a woman who, idly yearning for "a new and freer life," suddenly finds herself sucked into a journey of prolonged fear and gradual self-discovery. It is followed, unfortunately, by a second novel in which the same woman is nursed back to health, falls in love, and returns home to accomplish her final liberation; this novel might be described as superior women's-magazine fiction.

The woman is named Nancy Finch. She is 34 years old, the librarian at a small town in western North Carolina, unmarried. On a trip to the mountains with her sister and brother-in-law, they are accosted by an armed man who, after robbing them and cleaning out their camper, decides on a whim to abduct her. His original intention had been to drive to Florida; now, again by pure caprice, he decides to head west. For the librarian, life seems to have decided to imitate art: "When the man with the gun stepped out of a laurel thicket, she knew that part of her had been waiting for him ever since she memorized 'The Highwayman.'" But she quickly learns that this sallow, "colorless, motionless" man is no knight in shining armor:

"The way he spread strawberry jam across the toast distracted her, how he thinned it to pink film on each slice, carrying it neatly to the rim. 'This was just a weekend vacation,' she said, staring. 'I asked Faye to stay home so I could take a cruise but she offered this instead with her and Eddie. We go through this every summer.' On shipboard, Nancy had hoped to meet a man who would give her his full attention, would offer to take her away from all that; she had even prayed in the choirloft for such an encounter and promised no longer to be choosy about the man's habits, or income, or even intelligence. This man was God's answer? There were divine practical jokes John Calvin had never guessed."

The "that" from which Nancy wants to escape is her home in North Carolina, where her elderly mother and epileptic, mildly retarded brother depend on her constant attention and, as a result, chain her to the house. As she slowly works her way westward in Dwight Anderson's loathsome, dangerous company, she is deeply torn: On the one hand she is in peril and wants to be rescued, on the other she realizes that abduction has granted her an escape from home. So she proposes a deal: "Promise not to hurt me in any way. . . . And I want you to decide when you'll let me go and say so. . . . If you do that, Mr. Anderson, I won't try to get away." He says he'll let her go in Arizona.

Soon they become a party of three, picking up a dotty old hitchhiker named Harvey T. Jolley, a Tennessee country judge whose wife was recently killed in an auto accident and who is facing charges of misusing his office for personal profit. He too becomes a hostage to Dwight Anderson, who plays his two captives against each other in a casual, malicious game. As they move toward Arizona, Nancy has numerous opportunities to call for help; yet either she is too nervous to do so or the people whom she contacts cannot recognize her danger: "Nancy saw that nowhere in America was there a bellboy or waitress or gas attendant who could distinguish abduction from marriage or cared to try."

At last they reach Arizona; Dwight breaks his promise. So Nancy escapes, with the help of a woman parked nearby in a trailer camp, and flees to the Grand Canyon. Dwight, aware of her burning desire to see the Canyon, pursues her there; they meet in a singularly dramatic confrontation at the climax of which he loses his balance and falls to his death. Nancy, though suffering terribly from the heat, finds safety. At this point the novel is over:

"She filled her canteens, her canteens, at the tap. She bought more ginger ale, bread, two tins of potted meat in case she should ever be able to eat meat again. She did not have to decide yet what she would tell or to whom she would tell it. She circled the small building and sat with her back to its wall, alone, listening to the wires singing in the hot wind and wondering whether there was anyone overhead she really wanted to telephone."

The novel is over, but it does not end. Betts, who in her short stories knows exactly what to leave out, continues the story for another 144 pages. Certainly she satisfies the reader's natural desire to learn how everything comes out; she even supplies a happy ending. Yet after 215 pages of tension and psychological ambiguity, all of it strongly sustained, Heading West comes to a halt; the animosity between Nancy and Dwight, and the sexual tension, and the growing bonds between them-- these are the cement that holds the novel together, and without that cement the novel has no core, no unifying center.

To be sure, Heading West is about solid, provocative themes: the clash between independence and family loyalties, the relationship of art and life, the randomness of fate, the mystery of love, the allure of evil. And heaven knows the novel is beautifully written, in prose that impresses itself on the mind without calling attention to itself. But its structural difficulties diminish its many accomplishments; the short story remains the from in which Doris Betts is most comfortable and successfully