The myth of the prophet William Gibson was born in the early nineteen-eighties, with the wild success of Gibson’s début novel, “Neuromancer,” and the stories collected in “Burning Chrome”: he was heralded as a “cyberpunk noir-prophet,” the “prophet of the information age” who coined the word “cyberspace” while still banging away on a typewriter. As the distance from that first novel has grown, the myth has only expanded: in 2012, PBS’s Idea Channel declared that Gibson “had a better batting average than Nostradamus” and had “predicted the Internet.” (In fact, the Internet predated “Neuromancer” by years, and never much resembled that novel’s vision of a “consensual hallucination … lines of light ranged in the nonspace of the mind.”) Gibson’s own repeated admonitions that “science fiction is never about the future” and that “this whole idea of the predictive capacity of S.F. is so tedious and wrong” have had little effect. This fall, in anticipation of the release of “The Peripheral”—Gibson’s first novel in four years, and his first work of sci-fi this century—New York ran a sidebar called “Oracle Watch: A (Very Partial) List of Everything William Gibson Has Predicted Over the Years,” crediting Gibson with foreseeing Google Glass, normcore, the gentrification of San Francisco, and the rise of “competitive unpaid internships.”

But, in the decades since the release of “Neuromancer,” Gibson has moved away from the feverish neologisms and romantic hacker-cowboys of his early work. After that book’s much artier sequels, “Count Zero” and “Mona Lisa Overdrive,” Gibson abandoned what he called “full-on this-is-the-future genre sci-fi” for the more intimate, satirical “Bridge” trilogy. At the turn of the century, he abandoned sci-fi entirely, setting the chilly, paranoid novels of his “Bigend” trilogy in a present day thoroughly permeated by globalized capitalism and militarism. “Pattern Recognition,” the first book in the series, was written in the immediate aftermath of 9/11, and Gibson’s abandonment of the fictional future seemed driven by something like confusion, or even despair. As Hubertus Bigend, the outsize avatar of branding and capitalism who sets the plots of all three books in motion, explains, “Fully imagined futures were the luxury of another day…. For us, things can change so abruptly, so violently, so profoundly…. We have no future because our present is too volatile.”

“The Peripheral,” which is set in two related futures, might seem to mark a return to Gibson’s sci-fi roots, but in fact it demonstrates how far he’s travelled since he last wrote a novel of this kind, and what a fascinating, frustrating writer he’s become in the meantime. Half of the book takes place a few decades from now: 3-D printing (“fabbing”) is widespread, Homeland Security (“Homes”) is the main federal law-enforcement agency, drones are everywhere, and much of the American economy has collapsed into drug dealing and corruption. These chapters follow Flynne Fisher, a young woman who works odd jobs (such as playing video games alongside wealthy clients) to support her ailing mother. Her older brother, Burton, is a special-forces veteran who suffers from something akin to P.T.S.D. owing to the “haptics” installed in him by the military—“like phantom limbs, ghosts of the tattoos he’d worn in the war, put there to tell him when to run, when to be still, when to do the bad-ass dance.”

The book’s other story line takes place seventy years after the first, in a suspiciously underpopulated world of pervasive nanotechnology, in which dust and grime are practically nonexistent as a result of microscopic “cleaners,” impossible feats of construction are achieved by similarly tiny and ubiquitous “assemblers,” and everyone has their computers installed, diffusely, in their bodies. The “peripherals” of the novel’s title are a commonplace, if somewhat expensive, tool—essentially surrogate bodies, controlled remotely as if they were the user’s own. Some are organic and semi-human, others are entirely other; late in the novel, one character learns to control a weaponized robotic cube. Our guide to this world is an ineffectual, alcoholic, incongruously idealistic P.R. man named Wilf Netherton.

It is soon revealed that the two futures are in contact with each other: a mysterious, never explained “Chinese server” allows a few inhabitants of Wilf’s era to communicate with Flynne’s; soon enough, both characters are embroiled in a rather opaque murder mystery, and Flynne is spending much of her time controlling a peripheral in Wilf’s twenty-second-century London. This intertemporal communication also causes the two time lines to diverge; for better or for worse, Flynne’s world will no longer grow into Wilf’s, because Wilf’s past did not include this futuristic intervention.

It’s a clever, involving structure, and a way of exploring one of Gibson’s pet ideas, that “every future is someone else’s past, every present someone else’s future.” (It also reflects his rejection, in recent years, of the idea of “future shock,” once central to his writing: Flynne and her companions rarely seem more than mildly surprised by the strange new world to which they are suddenly exposed.) But the book built on top of this structure is one of the weakest Gibson has ever written. One thing that is immediately clear is how flat and attenuated his prose has become. In his early books, he wrote with a mix of pulp velocity and an odd techno-mysticism that bore the influence of Burroughs, Pynchon, and Dashiell Hammett; he often came close to outright silliness, but with a skewed, unmistakable force. There’s the famous opening of “Neuromancer”: “The sky above the port was the color of television, tuned to a dead channel.” Or this, from the later “Idoru”: “Between stations there was a gray shudder beyond the windows of the silent train. Not as of surfaces rushing past, but as if particulate matter were being vibrated there at some crucial rate, just prior to the emergence of a new order of being.”

In “The Peripheral,” the influences have fallen away, along with much of the goofiness, and what’s left is too often simply threadbare. This is Flynne, contemplating the damage done to her friend Conner, another veteran: “Whatever had happened to his mind, she suddenly knew in some different way, had been the worst…. She felt tears starting. Sat down fast, on the opposite end of the sofa from Burton.” Near the end of the book, as Flynne rides with Wilf to a showdown with the story’s main villains, she notes that “the interior of this car felt larger than the lounge in the Mercedes RV. It wasn’t, but it felt it. The way grown-up furniture felt when you were little.” Gibson’s prose was clipped and cold in his Bigend books, but there it generally added to the mood of paranoia and sterile greed. Here, it often makes what are supposed to be intelligent, perceptive characters seem anesthetized.

But more important is the way that the novel seems to be actively opposed to itself, its plot and characters increasingly irrelevant to its real concerns. Gibson is a radically materialist writer; a central tenet of his work is, as he wrote in Wired in 2001, that “all cultural change is essentially technologically driven.” In an interview with the Paris Review in 2011, he spoke of past existence and past technology interchangeably: “It’s harder to imagine the past that went away than it is to imagine the future. What we were prior to our latest batch of technology is, in a way, unknowable.” This world view is one of Gibson’s most distinctive qualities, and the reason he is, even at his worst, always worth reading: he is our great writer of man-made things. “The Peripheral” is full of arresting, provocative inventions, often simply mentioned in passing. Heading out into the rain, Flynne slips on an old parka with “that evil hydrophobic nanopaint on it…. The rain made a little sizzling sound, as it tried its fastest to get off the coated cotton.” Ash, an inhabitant of Wilf’s future, has animated, autonomous tattoos of wildlife all over her body, “a terrified tangle of extinct species, their black ink milling against her luminous pallor.”