At the center of a colossal clash : CANAAN by Charlie Smith (Simon & Schuster: $17.95; 416 pp.)

Elizabeth Bonnet Burdette. Of a sudden, one of the most extraordinary presences of modern fiction--enthralling, disquieting, ultimately unknowable to all save her creator.

We are spellbound by Elizabeth, totally involved with her, but not of her. Nobody--nothing--could be as free.

Elizabeth, a woman whose lambent transience--like that of a rare, brilliant butterfly--illumes and delights. And dooms: Woe to him who falls in love with a butterfly.

Around her is fabricated a novel, polished and repolished until the veins stand out. To outline the story is almost irrelevant: The larger tale centers on the colossal clash of liberty (license?) versus convention.

Jackson Coleridge (J.C.) Burdette III, fulcrum of the land-holding Burdette clan of south Georgia, meets Elizabeth in Hawaii during World War II and does what every man in the world--before or since--has wanted to: He marries her. Elizabeth: “He can have me, I thought, if he is willing to go through what I am going to put him through, and that’s everything there is on earth.” Elizabeth is not whistling Dixie.

A son, Jacey, is born. J.C. returns to Canaan, the ancestral 25,000 acres he is wresting by force of will into the 20th Century.

Elizabeth does not immediately follow, preferring to frolic in Hawaii with whomever, whenever, every day a cotillion. In time, she comes to Canaan, but in spirit she never comes “home.” (“I am always in the same place, exactly where I want to be.”)

About the Burdettes: “Their ambition was to get everything their territory could give them . . . to transfuse their own lives with the power and abundance of it . . . compelled to subdue.”

There are the requisite Southern-novel eccentrics (but blended skillfully, molded rather than strewn): J.C.’s father Jack, evicted by his own driven son, who ritually throws stones at the main house in the dead of night “for the good feeling that’s in it.” Drunken Delight Burdette and guardian/keeper Bernard, who run a fetid zoo. Rooley Burdette, a tempest on a palette, who flies over to spray-paint silver on the tops of 1,000 acres of pines.

About Elizabeth--surpassingly impulsive, self-centered, amoral (houseboys, strangers, women, family; she even “wished she could dig up old Langston (founder of the dynasty) and have a go at him”), so flighty as to make quicksilver seem stodgy:

“She had no plan, only an attitude, and approach.”

She sees the world not to be conquered but “as a delight to experience, a confection.”

“Her life was a trip without a destination. . . . The pleasure in it was seeing something new.”

Elizabeth fits into Canaan like a Dervish at High Mass--but only sporadically. When the mood takes her, she shoves off downriver on a johnboat to lie with J.C.’s best friend; glides to the Caribbean to live and love among the natives; rides to the woods to become one with the wildlife (an easy metamorphosis).

She returns, never through duty--a word she does not recognize--but through a particular unfeigned affection. “I have loved everyone, she thought, but they never understood it”--an understandable reaction to a girl/woman who drives a car off a bridge out of sheer exuberance, who torches the family mansion, who tries to drown her sister-in-law, who shows up at her son’s Baptist baptism on a Harley-Davidson, wearing a rhinestone kidney belt and a fruitwood rosary. . . .

Bursting from between covers meant to contain more homogenous mortals, it is Elizabeth’s book, Elizabeth’s life, a remarkable first novel of elusive but elemental force.

Says son Jacey, caught in the middle, to Elizabeth: “I wanted a story I could follow. This one hasn’t made any sense at all.”

It has, but only to Elizabeth.