Joseph O’Connor, an Irish novelist and playwright, is best known in this country for Star of the Sea, a remarkable and affecting novel set on a passenger ship traveling from Ireland to America in the winter of 1847, at the height of the great potato famine. In Redemption Falls, he has kept many of the novelistic techniques he used so well in the earlier book - multiple points of view, letters, fictional documents and pseudo-authorial footnotes. But while “Star of the Sea” gained power from its disciplined compression of setting and the linear clarity of the voyage, this new book sprawls across a vague, unmapped space that resembles mid-19th-century Montana and has no more linear clarity than a swatted beehive.

In 1866, Gen. James Con O’Keeffe, an Irish immigrant and (in many eyes) disgraced Union Army veteran, is acting governor of a region known simply as “the Territory.” Its capital, the town of Redemption Falls, has attracted a host of wildly different characters, creating a cross section of voices, chiefly Irish. Among the loudest are those of a poet from New York who also happens to be O’Keeffe’s estranged wife; a furiously bitter former Confederate soldier, now an outlaw; and a 17-year-old girl, traveling on foot from Baton Rouge in search of her brother.

In fictional if not Euclidean geometry, parallels do meet. Sometimes we follow the girl and the outlaw on the road; at other times and in no particular pattern, we encounter the girl’s brother, a freed slave, O’Keeffe’s poet wife, her adulterous lover and half a dozen other figures. But though we may loop back in time to the Civil War or as far away as a convict prison in Tasmania, these stories and voices all converge on the enigmatic figure of O’Keeffe, who waits brooding and drunk - and definitely unredeemed - in Redemption Falls.

One of the purposes of literature is, as Dr. Johnson said, to bring realities to mind, but no one is likely to mistake these characters for actual people. This is partly because - a considerable mistake in a historical novel - their actions are so detached from historical particulars. But it’s mostly because on virtually every page O’Connor’s hyperkinetic prose throws up a dancing screen of rhetoric that obscures both plot and character.

This style can be memorable: on a hot road Eliza “blisters in sunroar” and “the land unspools like a painted diorama.” It can also be very funny: “Cows enstalled, staring like a row of nuns.” And Eliza’s stream-of-consciousness observations can even be strangely poetic: “Burnt cotton in the air. And rooks. And scorched banknotes. Strange confetti, those gallowsblack angels.”

But too much rhetorical cleverness leads O’Connor to narrate his violent climax at a distance, through formal transcripts and official reports, at the cost of immediacy and drama, as if we were observing the action through the wrong end of a telescope. And far too often his language collapses from the poetic into the absurd (making love, O’Keeffe and Lucia “clunk like the couplets of a youthful sonnet”) or grows unbearably pretentious (“And on lurches the boy, gangly in his drabs, stumbling over cairns of the unseen eyes, which lie around the stubbles like the umlauts in the depths of a type-compositor’s drawer”).

“Oh rocks!” says Molly Bloom, drumming her fingers in impatience. “Tell us in plain words.”