Colum McCann's expansive new novel, his first since 2009's National Book Award-winning "Let the Great World Spin," opens with an extraordinary image of gulls dropping oyster shells onto the slate roof of an isolated lakeside cottage in Northern Ireland.

It foreshadows the strengths of the narrative he is about to unfold. When McCann is engaged with the particularities of place and character, on either side of the Atlantic, he is in the premier league of contemporary novelists. Whether he is imagining the cold beauty of ice farming in the post-Civil War Midwest or the unlikely visit of the great abolitionist Frederick Douglass to hungry Ireland earlier in the same century, McCann is both meticulous and sympathetic.

Paradoxically, within this constellation of Irish-American stories, it is the more recent past that is trickier to imagine. The most daring and compelling section of the novel sees us following Sen. George Mitchell to Belfast to referee the 1998 Good Friday Accords, the peace agreement that allowed a slow, humane melt of a deep political freeze to begin.

As he's shown before with his elemental story, "Everything in This Country Must," Northern Ireland galvanizes McCann's writing. He approaches that often-fraught subject with a necessary combination of tact and boldness that few other writers, British or Irish, Northern or Southern, have matched. Here, through the subtle Mitchell, he's also able to take a shrewd long view of Anglo-Irish relations: "They are stuck now on a point of language. The British and their words. The Irish and their endless meanings. How did such a small sea ever come between them?"

This is an optimistic novel. "What a surprise it is when distance finally breaks," muses Emily Ehrlich, a Newfoundland journalist who is part of a maternal line of characters that threads the novel together. Ostensibly, she's talking about the derring-do of Alcock and Brown's 1919 pioneering transatlantic flight, but the distances bridged in the book are temporal and emotional, as well as geographical and political.

Not all of McCann's bridging strategies are entirely successful. When he gets away from the sure ground of the particular and into the peat bog of the general, the writing can turn a touch sententious: "We return to the lives of those who have gone before us, a perplexing Möbius strip until we come home, eventually, to ourselves."

I wish McCann had allowed the narrative correspondences to speak more for themselves and spent longer with the characters, given us even more of his imagination. There are some tentatively explored fictional avenues. We meet, briefly, a shabby philatelist, and McCann's last narrator, Hannah Tuttle, remarks, "Belfast is full of odd people who have hidden away from the Troubles: they live inside tiny spaces and enormous imaginations." Introductions, please.

It would have been grand if this world could have spun a little slower, longer.

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