THINKING NEVADA to be Utah was one of Ilka Weissnix's first mistakes in America. But the geographical goof is just one in a stream of ever more endearing errors committed by the pale blond 21-year-old Viennese immigrant upon her arrival in America: errors of judgment, geography, taste, and language are all part of her initiation. Backward into sentences she throws herself, nouns and verbs inverted or all a-tumble, her adventurous grammar a telltale sign of her breakneck plunge from Homeland into Wonderland -- America in the 1950s.

In vintage Saturday Night Live shows, Dan Aykroyd fathers over the Conehead family -- pointy-topped aliens who try to act like earthlings by swilling beers (cans and all) and eating potato chips (bags too). Ilka's errors, of course, are not so exaggerated, but she shares with the Coneheads the courage to stick out her neck (or cone) -- to not just mingle with the masses but party with them. Installed by her cousin in a West Side New York apartment, Ilka does not tiptoe the rooms' perimeters or huddle with other recent arrivals at the corner butcher shop. Before she has learned either English or the New York subway system she hurls herself into both:

"'How ?' Ilka asked the woman at the employment agency who told Ilka to come back when she had practiced her English. 'With whom shall I praxis? You are the only American I met in New York? The onlies others I met are in my English class, which are yet other outlanders, which know always only other outlanders, which know yet lesser English as I!' The woman on the other side of the desk drew her head back . . . 'New York,' she said to Ilka, 'is not America, like all you people always think.'"

To try to understand this new world, Ilka must first get more confused. And so her cousin offers her a week's trip West, a train ride deeper into Wonderland, during which Ilka stops ever so briefly in "Utah" where she wanders into a saloon and almost immediately falls in love with a portly, older, whiskey-drinking, intriguing and, as she later learns, black man.

Lore Segal's third novel is named for this love affair. Carter Bayoux, the black man at the bar, is -- to Ilka's extreme good fortune and increasing sorrow -- her first American. Ilka's blank slate is suddenly scrawled with Carter's very intelligent, very sensitive, and yet very jaded view of America. He is an experiencer, a raconteur, a charmer, a participater, a rebel, a critic, and often a mean- minded, destructive alcoholic. Upon his and Ilka's return to New York he introduces her to America through his mind-broadening circle of friends and at the same time pulls her into the constricting ring of his craziness.

BEFORE LONG, the fractured English of Ilka's early days becomes almost correct; social situations are less jagged. But Ilka is not just Americanized by Carter, she is individualized, freed from being just one of the huddled masses. When Ilka's long-lost mother arrives in America, she is traumatized from both the death of her husband at the hands of the Germans and the shocks of transition: the warm golden pre-Hitler mornings of Viennese coffee and buttered rolls have turned into dark nightmares in which she dreams the Germans torture her still as she huddles in a corner of Ilka's apartment. The mother is the stark and frightening contrast to the daughter, a reminder of what the daughter might have been had she been less resilient, less brave, less prone to falling in love with such a character as Carter Bayoux.

The joy of Ilka's discovery of America fills this story, but sadness seems to win. Page after page of Segal's endearingly created immigrant does not prepare us for her end: the bright and feisty Ilka, who has learned to drink whiskey, make love, listen to jazz and mix it up with an unconventional group of friends -- Jews, blacks, and a few WASPs -- is allowed by Segal, almost overnight, to capitulate.

With Carter suddenly gone, Ilka's feisty spirit sags. She settles down and marries a simple, uneccentric loving man and begins to raise a family. And while readers were prepared for the naturalization and Americanization of Ilka, they are not prepared for her normalization or, worse still, the threat of her eventual suburbanization. The Coneheads tried to fit in -- sort of; but they never went so far as to lop off their telltale points or to install a rec room. But for Ilka, her first American is gone, having left his mark as first loves always do. And so she dissolves into the crowd and surrenders to what brought her and other immigrants to the shores of the New World in the first place -- the American dream. Only too soon she will truly be an American, but not until she learns how bittersweet that dream is.