Some novelists hate to share personal details, but Paul Auster has never been among them. Duly celebrated for the spooky realism of fictional tales like "The New York Trilogy" and "Leviathan," Auster has also written a string of increasingly eccentric memoirs. One reckoned with his early professional failures. Another catalogued the "physical pleasures and physical pains" of his first six decades. A third focused on his fuzzy first memories and the workings of his mind.

Auster's latest effort is a novel — his first since 2010's "Sunset Park" — but it's very much in keeping with his autobiographical inclinations. At almost 900 pages, "4321" is easily his longest book, a bona fide epic that manages to be both accessible and formally daring.

"4321" is divided into four parts, each of which centers on a young man named Ferguson. All of the Fergusons were born in 1947 (like Auster); all spend their formative years in and around New Jersey and Manhattan (ditto).

Though superficially similar, the four Fergusons have markedly different experiences. One is gay, the others straight. One dies during adolescence, a second skips college in favor of a bohemian existence and two others attend northeastern universities. One loses a parent in a tragic accident, another is badly injured in a car crash. It's these differences — a series of fertile what-ifs? — that inspire Auster.

The book's principal idea is that human beings are "a collection of contradictory selves," which can make it hard to tell if we've made the right decisions. As one of the Fergusons puts it, "You'll never know if you made the wrong choice or not. You would need to have all the facts before you knew, and the only way to get all the facts is to be in two places at the same time." Or in the case of this book, four places. The Fergusons, Auster says in the last chapter, are "three imaginary versions of himself, and then himself thrown in as Number Four for good measure."

This book contains some of the most perceptive writing of Auster's career. His multipart narrative gives him ample room to explore the vagaries of identity and, as he put it an earlier book, "the music of chance." But "4321" can also be frustrating. There are extended set pieces that would've been just as effective at half the length and lots of stream-of-consciousness sentences that, at 200 and 300 words long, will try the patience of even the most assiduous reader.

Auster, though, works hard to place his characters within the context of their times, and his efforts are almost always successful. There are long, vivid scenes about campus culture during the Vietnam era, life during the 1967 Newark riots, the curious pleasures of automat dining and the thrill of watching a 23-year-old Willie Mays chase down a fly ball.

Meanwhile, the story line in which one of the Fergusons decides to become a writer is hilarious and quietly thrilling. At first, he produces "twenty-three of the foulest stinker poems ever hatched by a citizen of the New World." But over time, he'll learn "to combine the strange with the familiar," to become "the most dedicated realist and yet to create a way of seeing the world through a different, slightly distorting lens." Which is what Auster himself has spent a lifetime doing, and what he does so effectively in "4321."

Kevin Canfield is a writer and critic in New York City.

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By: Paul Auster.
Publisher: Henry Holt, 866 pages, $32.50.
Event: 7 p.m. Feb. 15, Kagin Commons, Macalester College, sponsored by Rain Taxi. Tickets $5.