Oates' gothic epic: strange, oppulent; Bellefleur, by Joyce Carol Oates. New York: E. P. Dutton. $12.95.

"Bellefleur" enchants. It also alarms, frightens, even revolts. But most of all, it challenges. We must make sense of Joyce Carol Oates' vision of the mystery at the heart of life and of the book. "Bellefleur" continues themes Oates has worked before, in "Do With Me What You Will," "The Assassins," and "them," for instance. The world moves, not always toward meaning and certainly not predictably. Forces well up; passions overwhelm; fate, pure chance, and random choice mock the will.

The novel encompasses six generations, from the first Bellefleur, Jean-Pierre , to Germaine, the last, the child of Leah and Gideon. Jean-Pierre acquires the empire that flourishes most visibly when his grandson builds a 64-room house/manor/castle. According to the typical American myth, then, the empire begins to decline immediately until, in the fictional present, Leah sees her mission, to restore the Bellefleur empire and to clear Jean-Pierre II of a "life plus 990 years" sentence for mass murder.

The most sequential narrative centers on Leah and Gideon, on her growing independence in pursuit of her vision and on Gideon's growing estrangement and search for a substitute passion. Throughout that story we learn of the legendary Bellefleurs.

The episodic and flashback narrative falls into five dramatically structured books. Each book ends with one of Germaine's birthdays; she is 4 when the novel ends. Like another Germaine five generations before, she survives a family holocaust and brings the history full circle to another beginning. Each book also ends with an act of appalling violence. And each begins with images showing that an observer must construct the meaning of any history from random and disparate pieces.

A number of the Bellefleur bits and pieces involve storms, mysterious castles , vampires, shape-shifters, and so on. Readers won't believe in the gothic apparatus (for all the pleasure it gives), nor, doubtless, does Oates expect them to, but she does bring conviction to her gothic world-view and her fiction of "transformation."

Forms of that word occur at least 30 times in the novel, the concept innumerably. Some transformations, like the man who is really a bear, or Veronica becoming and unbecoming a vampire, or Johnny Doan becoming a hound, engage us solely for the wonder and the discovery that is in them. They do not convince, nor are meant to.

But their magic lends credence to the nonmagical changes against which they are juxtaposed. Leah is transformed from an austere, distant virginal beauty to a psychic figure, passionate, ruthless, harsh; Sheriff Ewan, vengeful and violent, becomes Christian and forgiving; the "Rache woman," Gideon's last lover , participates in his final act of suicide and destruction for no discernible reason. Because these radical transformations suit the gothic world of "Bellefleur," they do not perplex even though they are not psychologically traced. The tone and mystery of the novel and its world lead us to expect eruptions of the nonrational, inexplicable, violent, and passionate.

In the chapter "Once Upon a Time . . . ," for instance, we come close to the heart of the novel. The Bellefleur children learn through violent stories recounted to them of their nation and family, especially of the Varrell-Bellefleur feud, and through looking at a photograph of a black boy being lynched.

"Bellefleur" works in other mysterious ways. Jedediah, his vision of God blasted, finds that "single vision" is the worst sin. As his vision changes, so does his world. He descends from a 14,000-foot mountain and returns to the first Germaine, fathering the Bellefleurs that follow him. At the end of the novel, when the mountain is not his and no longer exalted, but Gideon's and linked with despair, it shrinks to 3,000 feet.

Like space, time also warps. Young Germaine's four years seem more like 20 or 30 for Gideon, and like aeons for Emmanuel, who maps and remaps the area but finds rivers changing course and mountains shrinking. His experience shows what several (I count seven) other characters perceive more explicitly: that the central fact of the world -- and its symbol -- is motion, change. The world is, and it changes, according to the observer.

"Bellefleur" delights with its opulence, its brilliant plotting, and its sheer strangeness. One occasionally and uneasily feels, while reading, that the book strains for effect, that Oates sometimes overwrites, that some characters and situations are perhaps just too weird. Yet in "Bellefleur," Joyce Carol Oates celebrates the imagination and revels in language (one not entirely atypical sentence is 61 lines long, but what a fine sentence it is, so terribly subtle at sustaining your attention while it winds this way and that). Most of all it challenges with a characteristically modern vision. Yet its conclusion, though muted and ironic, opens thought to hope.