CHARMING BILLY.<i> By Alice McDermott</i> .<i> Farrar, Straus & Giroux: 280 pp. $21</i>

“Romantic Ireland’s dead and gone / It’s with O’Leary in the grave,” Yeats wrote. Billy, the “charming Billy” of the title, is in his grave right at the start of Alice McDermott’s novel, which begins, in fact, with the 47-member funeral party having lunch afterward.

Billy, who quoted Yeats incessantly, represents the romantic strain in McDermott’s taut and beautifully written study of an Irish American clan. He was funny, warm, kind and graceful, and beloved by relatives and friends. He was their insouciant hero, their harp.

He was also their scourge, blight and death’s-head: an alcoholic who butchered both his own life and the illusions he raised in others. Scooped up from the street by the police, he lay in the Veterans Administration hospital, his lineaments black and swollen to twice their delicate and scholarly dimensions by the final explosion of an outraged liver.

“Charming Billy” is McDermott’s second venture at interweaving the realistic and mythical dimensions of Irish American life. She also wrote the superb “That Night,” a novel of teenage love in the suburbs, and her “At Weddings and Wakes” was a work of evocative detail whose narrative and thematic focus was not quite up to its emotional artistry. “Charming Billy,” by contrast, is intensely focused. It is a series of interrogations in disparate voices of Billy Lynch’s life and death.

McDermott’s writing never does fewer than two or three different things at once. Her realism is so blazingly accurate that it hurts; her doors catch our fingers, her food gives us heartburn. At the same time, each distinct atom of reality splits under her artisan hammer and releases a world of wild, lost particles: charm, for example, and others the physicists have not yet invented, such as grief, comedy, even happiness.

Every detail of the post-funeral lunch is not only right but so right that it links up to a disquieting universal accuracy. A blue-collar Bronx tavern with catering facilities (convenient to the cemetery), the long line of tables set diagonally across the back room (not often used and with a faint trace of mildew), a menu of canned fruit salad, medium rare roast beef, boiled potatoes, green beans amandine (my only cavil: I think it would have been misspelled “almondine”), vanilla ice cream in steel bowls, pitchers of ice tea and beer.

And yet--McDermott shuns categories--it is all surprisingly good. And yet--McDermott is an extraordinary writer--none of it is food: it is the sheer disembodied heaviness and dreamlike daze of a funerary event.

The first section is entirely devoted to the lunch. Like the virtuoso baseball section that begins Don DeLillo’s “Underworld,” McDermott’s leaves us breathless with the feeling of having glimpsed a universe and avid to explore it. Recounted by the narrator--a young cousin who has moved out West and brings a balance of familiarity and discovery to her account--the meal itself and all it suggests occupy only one level of the story.

Another is the narrator’s glimpse at the far-off end of the table of Maeve, the widow--universally praised for courage as well as “the courage it took to look out onto life from a face as plain as butter.” Yet there is a sudden surprising beauty in her, the narrator notices. For the moment, we will leave Maeve; she will be back. It is McDermott’s skill to lay down a number of sustained ground notes that rise in their turn and develop motifs of their own.

At the same time, at the narrator’s end of the table, Billy’s sisters and cousins are setting out his life. In a variety of versions, they praise his goodness and charm and lament his troubles with alcohol. They venture the story of his lifelong obsession, his marriage notwithstanding, with an Irish girl he had loved, sent money to and hoped to marry, only to have her die, it was said, of pneumonia. They flare into an argument that is the book’s thematic backbone.

Was Billy’s fatal drunkenness part of a grand romantic tragedy, as old Cousin Danny insists? Or was it simply a disease that would have gotten him anyway, as sister Rosemary asserts? It is the two strains: romance versus realism, the deadly poetry versus the deadeningly prosaic. Cousin Danny, himself a drinker with a blighted life, speaks out for poetry’s tribal ruinousness:

“Say he was too loyal. Say he was disappointed. Say he made way too much of the Irish girl and afterwards couldn’t look life square in the face. But give him some credit for feeling, for having a hand in his own fate. Don’t say it was a disease that blindsided him and wiped out everything he was.”

Through the remainder of “Charming Billy,” the voices and stories of the Lynch family will play out this root conflict between the allure and destructiveness of a culture’s romantic myth. Is it heroism or cowardice, a defiance of fate or a retreat from life? Despite the funeral debate, it is not an argument between one speaker and the other but within the speakers themselves. McDermott spins her novel around it with a grace and insight that withhold judgment but cannot be taken for indulgence.

The central figure in whom the conflict plays out is Billy’s cousin and best friend, Dennis Lynch. Through the narrator, who is his daughter, we hear the series of variations that are his life story. His mother, a maltreated orphan, escaped into marriage with a Billy precursor: a witty, generous man who filled their house with needy relatives and struggled for a meager living. After his death, she married a prosaic but prosperous shopkeeper. McDermott writes an entrancing portrait of a strong-minded, resolutely practical woman who seems militantly anti-romantic and turns out not to be.

In Dennis, the two strains mix painfully. He learns the prosaic truth of Billy’s Irish romance but hides it from him. (The scene in which Billy goes to Ireland expecting to visit a 30-year-old grave and finds something quite different is wrenching and sardonic; the discovery comes too late to change him.) Dennis seems to inherit his mother’s practicality; he makes repeated efforts to wrench his cousin from his alcoholic maelstrom but cannot stifle his own susceptibility to the other man’s crippled charm.

Through his daughter’s narrative, Dennis takes form in laconic and revealing bits and pieces. He is a limited man, by no means an entirely good man, and yet, finally, he represents a struggling openness to life. In another sense, so does Maeve; patiently practical through her married life while unable to do anything but love her wrecked charmer.

“Charming Billy” has the occasional limitation of any novel told purely in retrospect. It is like a landscape seen through a train window when riding backward. The clarity, nuance and resolution surpass that of the forward-riding view; on the other hand, you lose some of the exhilaration and rush. Sometimes the arguments repeat and grow static; notably in a long post-funeral scene between Dennis and Cousin Danny.

It is, nonetheless, a powerful and moving book whose wit and intelligence never supersede the lovely and unpredictable humanity of its characters. We are always with the Lynches. Sometimes, like them, we need to go out for air, but we also need, urgently, to get back.