Third-World Person Singular : LUCY <i> By Jamaica Kincaid (Farrar, Straus & Giroux: $16.95; 164 pp.) </i>

“Lucy” is transparent, like one of those models of the human body where everything is visible: bones, muscles, veins, lymph and digestive systems, and the organs. Everything except the soul, of course. But in “Lucy,” transparency is the soul. That, and anger.

The anger of Lucy, a 19-year-old who comes to New York from Antigua to work as an au pair, is an instrument of discovery, not destruction. It is lucid and cold, but by no means unsparing. In the book’s transparency we see it in delicate and painful dialogue with longing. It is the energy that propels her journey between distant places: between the Caribbean and the United States, childhood and growing up, the hunger for love and the hunger for autonomy.

Jamaica Kincaid, whose life is closely reflected in Lucy’s, has gone far beyond autobiography. At best, a biographical or autobiographical protagonist will be vivid and true. Lucy has ascended into fiction: She is vivid, true and necessary. Her voice in this harsh and graceful book tells us in the only possible way--at least while we are reading it--what it is to be a colonized subject, a Third World sensibility in the United States, a child battling with her past and a woman battling with her identity.

Lucy arrives in wintertime New York--cold is hostile--wearing new underwear that chafes--change is hostile--and stretched by contradiction. She is desperate to escape the poverty and oppressiveness of a tiny island and an overwhelming mother; she must struggle to be herself in an overwhelming new country.

From her bookish, argumentative childhood in Antigua, she imagines herself as Gaugin escaping bourgeois constrictions and turning hero in the South Seas. And in the tiny Upper East Side maid’s room that reminds her of a packing crate--”But I am not cargo,” she reminds herself--she realizes how far she is from her model: “I was not a man; I was a young woman from the fringes of the world, and when I left home I had wrapped around my shoulders the mantle of a servant.”

Lucy’s voice--detached, furious, shrewd and desolate by turns--tells us of no settled state but of a 19-year-old’s explosion into connections being made. She is lonely and homesick but consumed by the painful need to explore herself and the two worlds she is bridging.

It has taken some discerning foreign eyes--De Tocqueville’s, Bryce’s--to tell us things about ourselves that we did not know. Lucy, at work puzzling out the kindly, privileged and obtuse family she works for--Lewis, Mariah and their four blond daughters--has such an eye. The family is socially conscious by American standards. From the Third World, things look a little different. Mariah, the young wife and mother, is a romantic environmentalist, concerned about preserving nature against despoilment. Lucy thinks:

“I couldn’t bring myself to point out to her that if all the things she wanted to save in the world were saved, she might find herself in reduced circumstances.”

Mariah is a child of show-and-tell. She wants Lucy to love and admire the life she takes pleasure in. Lucy is a child of hide-and-consider. Her island was colonized, her ancestors slaves, and she is an au pair.

Think of yourself as part of the family, Mariah and Lewis had urged. Lucy reflects: “Aren’t family the people who become the millstone around your neck?” Mariah takes Lucy and the children to her family home in the Midwest that still means Arcadia to her. In the train, she wakes Lucy to look at the freshly plowed fields rushing by. Lucy, descendant of cane-cutters, thinks: “Well, thank God I didn’t have to do that.”

She will be sullen and scornful at first in this smiling, unconsciously smug family. Mariah is invariably fresh and fragrant. “The smell of Mariah was pleasant . . . but that’s the trouble with Mariah--she smells pleasant,” Lucy tells us. “I already knew that I wanted to have a powerful odor and would not care if it gave offense.”

Lucy, the glowering Third World making sandwiches in Mariah and Lewis’ smiling American kitchen, is much more than that. She is a child-woman with an unhealed wound of love. Her father ran around with other women; her mother was too crushing a presence to let her grow. Now she leaves her mother’s letters unopened and cannot stop thinking of her. “Half my life I’d been mourning the end of a love affair.”

The history of women’s pain, and the bond among those who suffer it, is something she cannot throw off. Bit by bit, she notices a hint of “ruins” in the blithe New York household; beneath her mockery of Mariah, the bond of pain is forming. Mariah’s hands arranging flowers reminds her of her mother’s. “I almost started to cry, I loved her so.”

Lewis, she discovers, is having an affair. For all his grace and kindness, he is no different from the men back in Antigua. “Everyone knew that men have no morals, that they do not know how to behave, that they do not know how to treat other people. It was why men like laws so much; it was why they had to invent such things--they need a guide.”

Lucy has her own succession of boys and young men; Kincaid writes of the affairs with comic insouciance. Sex is an untroubled hunger for her and none of her lovers touch her in any real way. But she carries with her a deeply troubling fantasy about a fisherman who groped one of her friends back in Antigua when she was a child.

She will leave her au pair job, remain friends with Mariah, find work as a receptionist, share an apartment with a New York roommate. She will continue to look at things and learn, coolly and voraciously; suspended between first and third worlds, between hunger and self-sufficiency, yearning and detached judgment. At the end, she has started a journal and has wept over the very first line: “I wish I could love someone so much that I would die from it.” She will turn the page and go on writing.