Sebastian Barry is a significant Irish writer and his new novel, set mainly in the United States, is a wonderful introduction to his work.

Barry started as a poet, and he puts that apprenticeship to good use by enlivening his prose with lyrical detail. "But there was something tugging, tugging at me now," narrator Lilly Bere says at one point, "some intimation, like a drop of lemon in a jug of milk, to sour it for the soda bread."

But it was as a dramatist, especially with the 1995 play "The Steward of Christendom," that Barry really came to prominence. With the imaginative overlap that is characteristic of his work, the "steward" of the title, Thomas Dunne, is Lilly's father.

As a high-ranking "policeman of the old British regime," Dunne and his family are, in an Ireland on the cusp of independence, what were known as "Castle Catholics" -- members of the majority religion who were loyal to the Crown. In fact, they are quite literally so, as they reside in Dublin Castle, the seat of British power.

However, in a story which emphasizes "how vulnerable any human creature" is, Lilly's youthful connections and decisions soon mean that her privileged position turns into that of a pariah.

Barry's breakthrough as a novelist came in 2005 with "A Long Long Way," which is the story of Lilly's brother, Willie Dunne, a soldier of the Great War. Lilly starts dating one of Willie's old comrades, Tadg Bere. He signs up for work as one of the Temporary Constables hurriedly hired by the British to help suppress the "Troubles" -- a paramilitary force that soon gained notoriety as the Black and Tans.

With a price on their heads, Lilly and Tadg flee to America. But even under "the generous American sky" Lilly cannot escape violence and the consequences of divided identities.

Lilly tells her life story as a near nonagenarian, in the shadow of the loss of her soldier grandson Bill, a veteran of the first Gulf War. In her late days, America appears to her as "a marriage between hope and suffering," which happens to be an excellent description of her own experience in the States.

Those American chapters introduce us to the novel's most memorable characters, including Joe Kinderman, her enigmatic second husband (another policeman); and the stoic Mrs. Wolohan, a Kennedy-esque wife and Lilly's compassionate employer.

The plot is beautifully crafted. Lilly's wanderings -- involving stops in New York, Chicago and Cleveland, before she finally comes to a kind of rest on Long Island -- make the story seem episodic, but Barry knows exactly what he's doing; the latter part of the novel has several convincing surprises.

The book is not entirely unproblematic. Lilly's voice frays at times, and a couple of the historical details are puzzling, though this may be part-and-parcel of having an 89-year-old narrator. All in all, "On Canaan's Side" is a vivid argument in favor of Lilly's (and indeed Barry's) contention that "there is nothing called long-ago after all."

Robert Cremins, the author of "A Sort of Homecoming," teaches in the Honors College at the University of Houston.