STONY BROOK, N.Y. -- And what is history, the sum total of all our lives? Or certain moments from certain lives? And if so, which moments, which lives?

1867. A bunch of Irishmen hoping to start a revolution march on an army barracks at Kilpeder, south of Killarney. They lie down behind a stone wall facing the ominously quiet building, through whose windows they can see watching faces. Their leader climbs over the wall.

"He stood upright then, placed the rifle carefully against his cheek, took aim, and fired ... There was silence. I could see from my angle, behind the hut, the most of the barracks. It had not changed, save for an immense, jagged hole, a wound, in an upper-storey window."

Are they making history?

Just such attacks took place all across Ireland in the so-called Fenian Uprising. The British stamped it out in a day.

Had there been nothing more, would the Kilpeder skirmish be simply another of the myriad incidents in the lives of that handful of rebels and militiamen and peasant witnesses? A line or two in a constabulary report?

One school of historians would say that it is precisely those obscure incidents and statistics that make history. But the scholar still has to select. Which obscurities? Which statistics?

Thomas Flanagan, who wrote the much-honored "The Year of the French," wrestles with this problem of life and history in his new novel, "The Tenants of Time." Kilpeder is an imaginary village, and all the people in it, so that their realities are in fact their creator's ideas. But perhaps, after all, this is the only way we are ever going to get close enough to an event to really understand it.

One of his characters is a young historian: neat.

"For at last Prentiss had, or thought he had, the shape, the design, the patterns formed by the pieces, the beginning of the narrative, when Ned Nolan, on a day early in 1867, walked into the town of Kilpeder, case in hand, and knocked at the door of his cousin, the schoolmaster Hugh MacMahon, to the night in 1892 when he broke into Brierly Lodge, murdered a man by putting two bullets into his chest, then fled, wounded, towards Clonbrony Wood and the distant Derrynasaggarts, and the circle, one of the circles, was rounded."

In the end, Prentiss doesn't write the history. He has got the big events lined up, "from the Rising through the Plan of Campaign and the fall of Parnell," but there are these other things, little things that are the stuff of life to you and me but hardly history. Two men in love with the same woman. A man bound to silence by loyalty. An exile somehow compelled to return halfway around the world to die on the scrubby, barren hills of his childhood.

A character muses, "Delaney drunken and abusive, slobbering in the house of his mistress, murderous furies tearing at him -- none of that gets itself into the books. Talleyrand or someone of that sort called history a lie agreed upon, but in fact there is little enough agreement. Sylvia's breasts pale and glowing above black velvet; Delaney's fury against the bishops, against anyone who dared to oppose Parnell; the savagery of his language: all that is history, or should be."

Prentiss tells a friend that probably the past can never be known.

Nothing wrong with that, the friend remarks. "A history is a kind of narrative, a fiction. I've always thought so myself, to tell you the truth."

Prentiss replies, "A taste for fiction ... has always seemed to me the unfailing mark of an imaginative deficiency."

In the face of that dictum, stern as only a youthful dictum can be, Thomas Flanagan has written an 824-page novel built around the wild and calamitous history of late-19th-century Ireland. It has the mark of greatness on it.

"When I wrote that line," Flanagan says, "I forgot I was writing a novel. I was so involved in the conversation between the two men. I read relatively little fiction myself. Used to read a lot of thrillers, mystery stories. But."

He shrugs. Last year someone reintroduced him to Francis Parkman's histories. "Wonderful books. I get all the pleasure from them I used to get from fiction."

He is sitting in the study of his rambling white house on the Long Island North Shore. Books are everywhere. Above his head is a solid wall of Proust and Joyce: books by, books about, books derived from. Beyond the great old fireplace, swaybacked shelves of books reach to the ceiling.

The ceiling is low, with smoke-blackened, half-petrified beams that bear ax marks, hewn, not sawed. This is the original cabin of the place known locally as Old Shinglesides. It goes back to 1754, when New Englanders settled on Long Island and gave it their look.

Flanagan agrees that once you have discovered Proust and Joyce, most other fiction pales. He sounds like an English professor, which he is. Born in Connecticut, educated at Amherst and Columbia, he taught English at Berkeley from 1960 to 1978 and now teaches at the State University of New York here. He is 64, the father of two married daughters.

And needless to say, his roots are in Ireland. With luck, as he says, he and his wife Jean spend three months of the year in a rented house at Rathgar, a Dublin suburb. He has been going there for 10 years and has been visiting the Old Country regularly for much longer than that.

This might help to explain his casual mastery of Irish speaking rhythms, the music in his characters' everyday speech ("Well do I mind that day in Cork City, and the three of us taking the oath from the Centre ..."), and his enduring love for the Irish landscape, which is more than scenery, more indeed than an extra character in the book. Even the indoor episodes seem compelled to shift to the outdoors sooner or later. People are always strolling out to the balcony to look at the night. Or this:

"A farmhouse is best for weddings, with the barrels of stout and porter wheeled in from the barn, and a fiddler to lean against the wall, the notes moving like quicksilver, in air heavy with tobacco smoke, the smell of food, drink spilled upon rough board or close-packed earth. A house too small perhaps to hold the celebrants, who stand chatting and drinking in the yard, and about them the natural world, the trees of summer, heavy-leafed. Evening darkens to night; voices thicken; the spirit, by spirits unchained, rises up; there is laughter, grace, clumsiness. A quarrel perhaps; a drift of insults, whiskey-fueled, soon resolved. Song, alone or entwined with violin, almost unbidden, a sweetness piercing the air."

When in Ireland, Flanagan gets up early, writes until midafternoon, then drifts into town to see his friends. He understands pubs, though a diet keeps him to a glass or two of wine, mostly. He has a theory that some cultures are visual, some aural, and while "an English pub can seem as civilized as a club, an Irish pub seems like a barn, really awful, but then, near closing time, somebody will begin to sing ..."

Even in dry spells he finishes a page or two a day. "The Tenants of Time" took him nine years, by the way, "only five or six in the actual writing." The rest was rechecking what he already knew about things like Japanese art, Whistler, the social and sexual habits of the Edwardian gentry, and roaming over the places where the story would happen, and as always, reading, reading, reading.

Halfway through, he says, the thing speeded up, "like a cart going up a mountain and down the other side," six or seven pages a day on his old Selectric.

He spends time in the west of Ireland too, in the Killarney district, where much of the novel takes place. Many of his closest friends are Irish -- the poet Seamus Heaney, the writer Conor Cruse O'Brien. And his grandmother on his mother's side came from Fermanagh in the north. She was married to an old Fenian rebel named Tom Bonner, who appears in the book, settled down with a brickworks on the Hudson River.

"I never knew him," the author says, "but my grandmother kind of raised me as much as my mother did, and there's something special about people raised by their grandmother, it's a different kind of connection with the past."

Which brings to mind William Faulkner, another writer with a grandmother. Flanagan doesn't like to talk about influences, but he admits he was conscious of the Squire of Yoknapatawpha as a historical novelist, notably in "Absalom, Absalom." Flanagan's novel has a distinctly Faulknerian way of circling, spiraling in on its truths, telling its story in tantalizing glimpses, partial revelations, leading the reader, by now avid and panting, through the narrowing labyrinth to the final, central, gigantic fact.

The tone, however, is measured and clear, enriched by some wonderful long, rolling Proustian sentences but lacking perhaps Faulkner's obsessive intensity along with his eccentricities. To the contrary, it's not out of line to say Flanagan's work recalls none other than Tolstoy, the patron saint of the historical novel. The critics who compared "The Year of the French" to Tolstoy spoke too soon. This one has even grander scope and more gripping set pieces -- the attack on Kilpeder, the eviction of a poor tenant from his hovel, a political rally, an assassination, and so on -- and characters who stay with the reader.

One will long remember Lady Sylvia, wife of the Earl of Ardmore, tall and arrogant and darkly beautiful, in love with Bob Delaney, the upstart politician, and aware that she is doomed.

She, like the others, belongs to her times and is never the costumed contemporary person so often found simpering self-consciously in historical novels. Her mores are Edwardian mores; her style, speech and attitudes, the very shape of her life, would be unbelievable in any other era.

"The Tenants of Time" will send many a reader to the atlas and even more to the encyclopedia in an effort to separate fiction from history. More than anything else, it is a keening for the fatal repetitiveness of Irish history. (Not surprisingly, the early working title was "Unexamined Lives.")

Just as Parnell's fall echoed that of his predecessor, Delaney's fictional fall echoes that of Parnell. Time and again, when the conflict with the British seems on the point of being resolved at long last, someone dies, someone loses an election, the House of Lords votes it all down ... and the whole cycle has to begin all over.

"The Irish have a passion for history," Flanagan says. "It's an Irish failing. That's what Parnell said, who himself had no sense of history whatever and is on record as having read only one book, 'The Horse.' "

This may be why, he adds, the Irish have always had trouble with their cultural identity. "It shapes their lives immensely. They can respond one of two ways: total assimilation into the English culture or total rejection of it." Celts and Anglo-Saxons, at it still.

Americans -- and he would never dream of identifying himself as anything else in Ireland -- are apt to see Ireland as a patriotic panorama, while "the Irish themselves tend to realize the complexity of the thing, how much it's grounded in people's lives and deaths."

Maybe it was the peculiarly human scale of Irish history, maybe it was his own interest in fiction (as a young man his short stories won prizes), or maybe it was his first book, "The Irish Novelists, 1800-1850" -- whatever the case, Flanagan found it an advantage to approach Ireland as a novelist rather than as an academic. It delighted him not to be using the scholar's everlasting 3-by-5 cards. He learned to trust to luck a lot, he says.

"As a novelist I'm entitled to keep the problem in solution," he observes. "I can keep the possibilities open. As a professor you have to say what you think about it."

Instead, it is the characters who express the thoughts and feelings here, a whole spectrum of them, so that they remain unresolved and open to the reader.

"I got my first idea for the book when I was in London and staying at a hotel on the Embankment. I could look up and down the river, to Westminster Bridge, to Tower Bridge, to the Houses of Parliament, those great huge Gothic piles, and I wondered what it would be like for a young Irishman to come here when this was the most powerful place on the globe, the center of it all, and he would realize he was pitting his strength against that huge power."

Just so does Bob Delaney see the river from the Embankment, and those thoughts are his thoughts. And other characters -- as a matter of fact, a significant number of the book's major figures -- are drawn to that spot as though it were a magnetic pole, the other being Ireland.

The novelist's privilege: The words come from the characters, but the characters come from him. It is a character, for instance, who gets to say, "There is one cause, and the one cause only, Patrick Prentiss, and don't you forget it -- a free people in a free land, the Republic of Ireland, and don't you ever forget it."

Flanagan doesn't talk much about his own political opinions when discussing his work ("that's what I did at length in the book," he retorted to one interviewer). He does say, however, that he was part of the university group sympathetic to the students during the Berkeley uprisings of the '60s, when he was an associate professor.

"I was sympathetic to the Free Speech Movement," he says. "I was in the anti-Vietnam war movement, I signed all the right petitions."

But he doesn't write about the American culture. It liberates him, he says, to write about the Irish culture.

Surely he is never far from that green dark country. He is the kind of person who in the middle of a conversation about movies jumps up from the lunch table and runs to the library to bring back a picture he's excited about. It happens to be an illustration for Joyce's "The Dead."

He is the kind of person who, when he took a taxi into Dublin on his very first visit to Ireland, startled the cabbie by instructing him to "go left at the Custom House and over Duke Street" and so on, for he knew the city intimately through reading Joyce.

He hopes the new novel that he is planning will enable him to quit teaching altogether. Half of it is situated in Ireland, but beyond that he's not talking about it.

He seems content in this creaking old house with its pantry walls papered in road maps ("it's why we bought it," his wife says), and the overweight cat named Kitten who alternately purrs and bites, and the 17th-century map of Ireland on the mantel, and the ancient fireplace and the books.

Photographers or no, he pads around in well-worn clothes like some Irish country squire, without his teeth, his victor's wreath of white hair afly, and you think about the 824 pages, the passion and intelligence, the tortuous circling and circling to come upon the truth, yet another, deeper truth, the grand pattern of it that he held in his head from the beginning.

And you wonder what he's got in there now, what new tumultuous vision of history and people's lives.