From the first moment you see him, it's clear something's different about Jonathan Lethem. Compared to recent photos, he looks more weather-beaten; a little older, maybe; more impressive. Laugh lines indent his cheeks more deeply; slips of gray tickle his sideburns.

It's a change that anyone who reads the 39-year-old's new novel might pick up on even without seeing him. From the book it's clear that this is a wiser and grander Jonathan Lethem, a writer who, if he hasn't completely shed the genre influences that made him first a cult and then a critical success, now wants to, and likely will, be regarded with the utmost seriousness. This is Jonathan Lethem the pop-culture critic, the social documentarian, the eloquent commentator on modern life. His generation's Don DeLillo, perhaps, if DeLillo had spent his youth collecting soul records and X-Men first editions instead of whatever it is DeLillo spent his youth doing—baseball cards, perhaps, and silver pennies.

Exhibit A for Lethem's case is The Fortress of Solitude (out this month), a sprawling, semi-autobiographical street epic that takes the white Dylan Ebdus and his black best friend, Mingus Rude, and tosses them into the popcorn-crackle of New York circa the 1970s and early '80s, where they dodge—and occasional indulge in—vice and violence. It is a story of regular beatings, where taunts of "F— you looking at?" are both rallying cry and racial signifier, in a pregentrification Brooklyn that, contrary to myth, is anything but innocent or pleasant. Highlighting the weightier Lethemesque themes of redemption, memory and, with the disappearance of Dylan's mother, parental abandonment, it also sprinkles in his trademark whimsicality via a ring that lends its wearer superhero powers. At once a hypergritty story of a city kid struggling to adulthood in a rough neighborhood and a dreamy fable overspilling with cultural and generational symbolism (Dylan! Mingus!), it is both urban documentary and urban fairy tale, an intoxicating amalgam of two kinds of unbelievable.

"The Fortress of Solitude is something I've been feeling the shape of a long time as a book I needed to write, without being completely clear on what would go in that shape," he tells PW as we meet him on a Brooklyn corner one overcast but stuffily warm July afternoon. Lethem is set to give us a tour of the neighborhood where he grew up and set his novel, and to which he recently moved back. Once upon a time it was called Gowanus, the same as a nearby housing project, but in a change he chronicles in Fortress, it has over the last decade or so become the Manhattan hipoisie suburb of Boerum Hill.

As we walk, we pass the French bistros and DJ lounges, but he's not here to show us this. He's here to give us a tour of a different Brooklyn, his Brooklyn, the Brooklyn that reveals itself, like a bottle's sediment, through a layer of clues that doesn't so easily wash away. Not far from trendy Smith Street, we come up on P.S. 38, Lethem's elementary school for a few years and one of the novel's main settings. "The Institute for Global Studies" reads the official writing on a handball wall at yet another school on our tour, where someone has used spray paint to cross out "Global" and replace it with "Thug Life." Welcome to Lethemville.

"Brooklyn has a weird nakedness. It's a place where the renovations that are so characteristic of American life never quite work. It's a place where the past and memory are lying around in chunks even after they've been displaced. It's permanently unsmoothed over," he says. As if on cue, a moment later we run into the Gowanus housing projects, another of the book's main reference points, which now lies in the shadows of flowering pear trees and repointed brownstones.

The neighborhood's complexity is at least part of the reason Lethem took so long to get around to writing about it. Inverting the usual tendency toward memoirish fiction first and more far-fetched material later, Lethem spent eight years publishing ambitious and at times outlandish novels that had little to do with his own background. For much of his early career he didn't even live in the borough that he has lately come to explore so colorfully; he spent a decade of self-exile in California until about five years ago, when he returned and finally began working on this book. "For years, I was overwhelmed by Brooklyn," he says. "The richness of my own upbringing was too much for me to contend with, either in my life or my writing, and so I was in a kind of flirtation. When you see me going back in the first couple of chapters of Girl in Landscape, you're seeing me daring myself to open that box and really let it come." Even 1999's Motherless Brooklyn, his NBCC-winning mystery set in fictionalized Italian-American neighborhoods, feels very stylized in a way this story does not. "As much as I seem to be taking the borough head-on, I was also turning it into a cartoon," he admits.

So after all the futurist westerns, the black holes with personality traits, the genetically engineered menial-worker sheep and, of course, the caricatures in Motherless Brooklyn, the novelist is finally ready to offer his real take. Not only on Brooklyn, but on perhaps the most mysterious subject of all: Jonathan Lethem. It is in this pursuit, in decoding what is and isn't real, that some of the fun of Fortress lies. While the book is categorized as a novel, and Lethem plays down similarities between his life and Dylan's—"The essential way in which this is autobiographical is milieu," he says—there are a lot of parallels: the lack of a mother figure (in the book, she runs away; in real life she died of cancer when Lethem was a teenager); an aborted stint at an entitled Vermont college (in the book, Camden; Lethem went to Bennington—but in The Rules of Attraction, Bret Easton Ellis made up the name Camden to refer to Bennington...); corresponding ages; a love of obscure but generationally representative records; a hippie artist father.

As he points out his childhood landmarks that appear in the book, he does so with a peculiar kind of unsentimentality. The abandoned building where children play with a Spaldeen; a local crack house; even his childhood home near the corner of Dean and Nevins Streets, do not appear to stir emotion. He keeps a level tone as we round the corner, commenting on how the block changes from the verticality of the elegant brownstones to the squat ramshackleness of fading local businesses. His default mood is coolness, not wistfulness; his chosen method of recollection analysis, not contemplativeness. If the conceit of the book is a gritty story cloaked in dreaminess, the conceit of Jonathan Lethem appears to be the opposite—a writer of dreamy prose draped in critical detachment.

Lethem's Choice

It's fitting that Lethem has claimed Brooklyn as his fictional territory; like the borough, Lethem is continuously renewing himself and reorienting his trajectory. He has gone from unknown to cult figure, breakout critical darling and now, if all goes according to plan, mainstream "great American writer," as a blurb from editor Bill Thomas calls him in a letter with the galley. "I really have been very lucky. I've gotten to have a slow-forming career at a time when that's supposedly not possible, and it's been a very natural process," says Lethem.

Thomas sees in Lethem's rise a very specific explanation—and a template for writers of lesser achievement. "The message of Jonathan's career is that if you focus on the words on the page and perfecting your art, you will succeed. If you worry about things like a huge advance and the right MFA program, you most probably will fail. If success is your goal, and not artistic greatness, you most probably will fail."

Lethem's first two books, both novels, came out from Harcourt, where he was edited by Michael Kandel, an editor and writer famous for his science fiction projects and for bringing to the U.S. Stanislaw Lem, the Polish novelist who Lethem acknowledges as one of his early influences. But Harcourt was undergoing some changes in the mid '90s—a rocky term as a division of General Cinema—so when an offer came from Thomas at Doubleday, Lethem and longtime agent Richard Parks decided he should jump, even though Harcourt was still set to bring out his third book, a short story collection called The Wall of the Sky, The Wall of the Eye. "[Thomas] told me he'd try to bring me a broader audience," Lethem recalls, "and I found his energy and enthusiasm irresistible." Lethem has been published by Thomas ever since, first with As She Climbed Across the Table (1997), then with Girl in Landscape (1998), then Motherless Brooklyn and now this, with time taken out for side projects like writing a short story for McSweeney's Books and to edit The Vintage Book of Amnesia (2000), a kind of concept album of stories that trade in memory and forgetting. Lethem has also positioned himself as a kind of North Star in New York's literary firmament, a role model and patron saint for the literarily upwardly mobile. He has been given big play for running games of "Mafia," an involved competition of loyalty and betrayal that attracts journalists and literati of all types.

His success is a process, which, also like Brooklyn itself, seems to entail, perhaps even require, an eschewing of what came before, a willingness to believe that what is now is what is true, and what is past is interesting but not terribly relevant. "There's no mistaking it—those books [before Motherless Brooklyn] are more hermetic. They're more inward," he says, in one of several comments suggesting a desire to put the earlier part of his career behind him (not unlike DeLillo). "My development is a story of learning to put more of what I know and feel into a book."

Lethem brings another dimension to his publishing career—a 10-year tour of duty as a bookseller, most notably at Moe's in Berkeley, Calif. That store is known for its deep collection of used books, and the long days and nights with the classic and the dog-eared reverberate through his work, in the genre conventions of his earlier books and the pop-cultural references of Fortress.

Despite all the differences between his earlier work and this book, there are some common threads, especially the shimmering chasm between reality and memory, between things as they were and as we wanted them to be. Or as Lethem might call it, amnesia.

"If you look at my books, they all have this giant howling missing center. Language has disappeared, or someone has disappeared, or memory has disappeared. I'm usually writing around a void," he says.

In Fortress, he has taken this void and given it new thematic heft, writing a book not just about childhood but about the process of remembering childhood, in all its dreamy impossibility. The childhood section of the book feels like it has been written years later by someone thinking back on it—it contains a lot of scene details and very little dialogue, in the way a long-buried memory might—with the switch from the third-person narration of a child's life to the first person of an adult's reinforcing that idea. "That gap is the subject of the book—that distance between the yearning to return to childhood magic," he says, "and the paltriness of adult experience."

As we wind up our tour, it's clear that perhaps the biggest memory hole is local: between what this neighborhood once was and what people wanted it to have been. "I grew up with these enormous antigentrification sentiments," he says, as we stand on the corner of two main streets, Bergen and Smith, where a Hispanic man walks out of a storefront lawyer's office while up the block a few well-scrubbed types gather for happy hour. "But now, from this distance, I see there are paradoxes under the paradoxes, and that the idea that there was a 'before' that was simple and good and a 'now' that is corrupt and bad is wrong. Behind the patchwork and contradictions of the present lie the patchwork and contradictions of the past."