By April Bernard

Norton. 240 pp. $18.95

SELF-INVENTION is one of the inalienable rights of all Americans, the major enterprise of adolescence, and the inexhaustible theme of the coming-of-age novel. Pirate Jenny is a first novel that presents the wilfull metamorphosis of the larval Connie Frances LaPlante, a 17-year-old virgin from an exhausted Massachussetts mill town, into the winged Jenny Freuhoffer, less butterfly than vampire bat.

Connie can't bear to go through life named for a very uncool singer from the '50s, nor, like most adolescents, can she believe that the working-class dolts who call themselves Mom and "the Dads" could possibly be her parents. By the time we meet Jenny, nee Connie, her father has split, though he drops by frequently to raid the refrigerator. Mom has a succession of boyfriends and jobs. Jenny herself works in the Root Beer Barn the summer between junior and senior year and dates a boy who is about to enter the navy. Jenny has bigger if inchoate dreams.

April Bernard, an award-winning poet, renders both Massachusetts and Manhattan with skillful economy while unobtrusively planting her symbols and leitmotifs. Synthetic dyes from the paper mill stain the river that runs through town and Jenny "had a shoe box collection of dyed rocks at home." This detail obliquely foreshadows the heroine's makeovers, even if it sounds geologically suspect. Bernard paints Jenny's hometown with intimate detail, even as she registers the heroine's prevailing contempt for her background. I felt a pang of nostalgia on the eve of her escape to New York, a feeling not shared by Jenny, who burns all pictures of herself and cleans her mother's house from top to bottom in order to eradicate all trace of her former self, including fingerprints.

Self-invention is seldom sui generis; there's usually an operative myth, a series of models. Significantly, Jenny likes Dickens, Frankenstein and Dracula. But the major makeover text is the songbook of Brecht and Weill, as sung by Lotte Lenya -- songs like "Mack the Knife" and "Pirate Jenny." (I can't help wondering if it's a deliberate comment on the heroine's thoroughgoing naivety that she chooses for her new exotic self such a girl-next-door name.)

After immolating, burying and Windexing all traces of her former life, Jenny steals a car and some cash and drives to a shopping mall in Connecticut, where she gets a new wardrobe and coif, and hitches a ride to New York, New York. In the car she introduces herself with her new name, Jenny Freuhoffer, which still sounds to me like a dessert made from potatoes, and tries out her new German accent, occasionally lapsing into a Peter Sellers French accent. Her experiments with clothing and makeup are similarly shaky at first although Jenny instinctively knows that where she can't fit right in, she will have to make an unabashed virtue of standing out; her sartorial long shots and her faux pas are interpreted as bohemian.

Jenny gets a job first as a hotel chambermaid, where she selectively pilfers clothes, shoes and jewelry, and then, more promisingly, as governess in a wealthy White Russian family.

Here in the bosom of the upper class she is able to study manners and refine her act. Early on she learns one of the eternal fashion verities: "Jenny's creed, reinforced by Netta, involved shoes -- how they said you were right, or gave you away if you were wrong."

Bernard's portrait of the eccentric family of Russian aristocrats is richly detailed enough to nearly vanquish inherent cliches -- powerful, wise matriarch, curmudeonly patriarch and all. For all of their old-world sophistication they soon prove to be foolishly vulnerable to Jenny's cynical charm and one wonders how much havoc and larceny Jenny will wreak on them. Unfortunately, not much. She steals some clothes, and for a while the boyfriend of her employer's granddaughter. She does let the house get incredibly messy while the family is up in the Adirondacks.

But Pirate Jenny never really comes through with the pillage and slaughter promised by her namesake, which is curious since the author goes to some length to establish her vigorous amorality. Jenny is a pathological liar and a kleptomaniac. When her unhappy mother traces her to New York and shows up on the doorstep one day, she is cruel enough to punch the older woman, knock her down the stairs and slam the door in her face. It's as if Bernard had introduced a gun in the first chapter, loaded it in a later chapter and then used it for target practice: ultimately, Jenny's capacity for violence, and her skills in larceny and mendacity, are only marginally exploited.

Jenny is shaken up by the encounter with her mother, but we never discover how she really feels about it, just as we never really understand her intense need to deny her antecedents. The narrative voice, while reflecting Jenny's point of view, generally maintains a discreet distance from her deeper thoughts and feelings. While the world through which she travels is often exquisitely rendered, the inner landscape is barely glimpsed.

For all her ruthlessness, Jenny remains something of a naif, and the con artist is herself conned when she marries a rich young heir who is not all that he appears to be. But Jenny outsmarts her new husband, and sails away, literally, with a new haircut, a new wardrobe and a new passport, continuing to work on her unfinished invention. I wouldn't mind seeing her again when she has worked up a prototype.

Jay McInerney's novels include "Bright Lights, Big City," "Ransom" and "Story of My Life."