One of the striking things about Colm Tóibín, perhaps the most admired Irish writer to emerge since John Banville, is the feeling in his work of a powerful sense of humour being strategically suppressed. Tóibín's writing isn't humourless; there are darkly comic scenes in The Master and some witty lines of dialogue in The Blackwater Lightship, and his journalism is frequently very funny. But in his novels, on the whole, he's so intent on leading his readers where he wants them without letting them catch him doing it that making them laugh too often might strike him as counterproductive. His fiction works hard to create the illusion that the characters reveal themselves almost independently of the narrating voice. It also aims to depict complicated feelings and interactions with a minimum of fuss and portentousness, using simple words and a precisely controlled tone that implies a certain hush.

Tóibín, it should be added, has serious interests. These include Catholicism and the legacy of Irish nationalism, the inward sufferings of gay people throughout most of history, and difficult emotional currents within families. Spanish and Latin American politics are part of the background to The South and The Story of the Night, and he touches in several books on the devastation done by Aids to gay men in the 1980s. He writes well about women, often putting them centre stage, and about people who feel compelled to hold their feelings at a distance, his Henry James in The Master being a good example. At the same time, he loves form and imposes strict rules on himself concerning point of view and narrative manipulation, rejecting tricks as firmly as Raymond Carver did. His plain style is unostentatious even in its plainness, avoiding musical balance but also taking care not to seem mannered or excessively clipped.

In Brooklyn, Tóibín continues to conjure strong emotions from the gaps between his lines, but this time humour has more of a place in the range of available tones. He fits it in partly through lightly comic dialogue. "No one likes flies," a haughty Wexford shopkeeper tells the heroine, a young woman named Eilis Lacey, "especially on a Sunday." Yet the jokes aren't free-floating. Tóibín gives Eilis - whose point of view is strictly adhered to throughout - a well-tuned ear for such speech, which she uses to entertain her mother and elder sister. The reader quickly sees that there's something brave and sad about her spirited performances over the dinner table in the economically stagnant provincial Ireland of the early 1950s. Her father is dead; her older brothers, much missed by her mother, are working in England; there are few prospects of marriage and few jobs in Enniscorthy.

Eilis's sister Rose, whose earnings from an office job support the family, plays golf in the evenings. At the club she meets a priest, back from America on his holidays, who knew their parents years before. The priest offers to arrange a job in Brooklyn for Eilis, who soon finds herself crossing the Atlantic third-class, fully understanding that, by organising this, Rose has sacrificed her own future. Tóibín patiently dramatises Eilis's homesickness and her brushes with enforced American good cheer, her relations with her fellow inmates at an all-Irish boarding house, her work at a moderately enlightened department store, her night classes, and her pleased discovery of all-night heating and affordable women's fashions. In time she meets a handsome Italian-American man who speaks seriously and tactfully of marriage. Then a death summons her back to Ireland, where she finds that America has made her glamorous and desirable, and faces a choice between the old life and the new.

This simple-sounding story takes on depth and resonance in a number of ways, starting with what it leaves out. There's no awed first glimpse of the Manhattan skyline; even the account of Eilis's first trip to a baseball game focuses on her boyfriend's way of being with his brothers, not the chance to write a set piece. Overemphasis is almost obsessively dodged. "'She'll be there. Nothing is any trouble now,' he said": most writers would have put the speech tag between the two sentences, but not Tóibín. Within his stern parameters, however, he's able to convey pathos, sharp observation, and finely detailed psychological realism. Brooklyn's symmetries and neatly circular plotting aren't camouflaged as heavily as the rest of its artistry, but there's no mistaking the book for a conventional historical weepie. The word "love" is applied more often to Eilis's feelings about her room or her textbooks than to the men in her life, and Tóibín doesn't sentimentalise his central character's experience of either country.

We're used to getting these kinds of stories from an American perspective in which moving to America is the natural thing to do. Tóibín makes his emigrant's story more painful without simply reversing those assumptions or ruling out an ironic distance from postwar Irish insularity. (A prim young woman from Belfast shares her views on Brooklyn's Italian and Jewish populations: "I didn't come all the way to America, thank you, to hear people talking Italian on the street or see them wearing funny hats.") Eilis herself is an interesting character, less defenceless and more troubled than she initially seems, and the novel uncovers the "dark, uncertain" areas within her with a very light touch. Her rejection of her landlady's proffered friendship, and her encounter with her sexually wistful female boss, are handled as delicately as any scene Tóibín has done, although here and there his delicacy doesn't exclude a note of ribald amusement as well as worldly melancholy.