So why, I wondered, would Richard Powers set "Plowing the Dark," his seventh novel, in a VR lab during the late '80s and early '90s? What interest could an overhyped and underachieving technology hold for a novelist who's taken on challenges as various as cognitive science (in "Galatea 2.2"), the DNA code (in "The Gold Bug Variations") and, most recently (in "Gain"), the history of the American corporation? Why squander a prodigious ability to wed metaphor to scientific language on material you can read about in a seven-year-old issue of Wired?

And do we really want to follow a fairly generic group of techies through 400 pages? I wasn't sure I did at the beginning, when Adie Klarpol, artist and emotional burnout, considers joining a team of VR designers in a Seattle start-up called the Realization Lab. Adie gets to state all the requisite antitech arguments, to register amazement at the moods and meshugas of Realization's hobbit-like denizens and, in record time, to tumble for the seductions of simulated space.

Luckily, we're seduced as well, because that's about it for the plot setup. The Realization programmers, engineers, mathematicians and designers are mostly interchangeable walking woundeds and socially stunteds, but what we watch them make is achingly beautiful. Their first prototype, a 3-D simulation of the jungle in Henri Rousseau's painting "The Dream," is a riot of joyous creation both in its rendered images and (at simulation's second remove) in the words that render the images:

Through the Jungle Room, birds wing at liberty. Define a feather when condemned to the wind. Say how the shaft tapers, straining to be weightless. Describe what the vanes do on the air, how they luff and ruffle and flute 

Their speculations about the political import of what they're doing are equally lovely and extravagant. I'll confess that I'd all but forgotten the flashes of loony technological optimism that accompanied world events like the Tianenmen Square demonstrations and the demolition of the Berlin Wall. "Maybe the spreading world machine was catalyzing this mass revolution," Spider, the team's hardware guy, muses. "Maybe silicon seeds had planted in the human populace an image of its own potential." The vision, briefly shared by cultural-studies radicals and hippie technomystics, went something like this: If you could only see the world -- if by building a complex enough simulation you could apprehend it both in its wholeness and in its working parts -- then maybe you could fix it. Maybe computers could help us to find, to create (in Powers' words) "places where we can change all the rules, one at a time, to see what happens."

Or maybe not. Maybe, as Ellen Ullman observes in the May issue of Harpers, what's happened instead is a radical narrowing of vision and aspiration. Does anybody think nowadays that, with the help of technology, we can change all the rules? Does anybody think of much at all beyond the solipsistic and infantile "my computer, my Yahoo, my my my"?

I don't know if Powers would see it that way, but I do think he intends us to consider the present that's rooted in the past he explores. "Plowing the Dark" is like near-future cyberpunk science fiction in a fun-house mirror: Powers evokes utopian technological aspirations of the near past and allows his readers to draw their own conclusions about the present.

But past and present are only one of the sets of oppositions upon which this novel is built. Powers lays down multiple coordinates, spins webs of interlocking narrative: past/present, real/simulated, macrocosm/microcosm. World-building isn't only a political matter; it's also a matter of how we find our bearings and balance within intimate social space. Like speaking prose, we do it every day.

And so an entirely unrelated narrative weaves its way through the VR story. While the programmers build Rousseau's jungle, Tai Martin, an American hostage in Lebanon, savors a hard-won concession from his captors -- a daily half-hour of freedom to move around his room as he pleases:

You pace about, astonished. From the once-mythical far side of this cube, you look back across the ocean of air. Seeing your corner like this, from a distance -- your mattress, radiator, chain; the grubby country that swallowed you entire -- it looks bounded, known, livable.

A dirty, windowless room in Beirut becomes the novel's ground zero. Martin's desperate and brilliant expedients to stay sane and human (drawn by Powers from many memoirs by political hostages) are as compelling as any of the book's computer wonder stories. His struggle -- to find world-making tools in a cruelly deprived environment -- is the thought experiment at the book's core, the dark background against which the flashy VR technology is projected.

"We're all scientists  every person running this little experiment in being alive," one character observes. The problem to be solved is an inhospitable world not of our own making. The experiment -- to remake it so as to make ourselves at home in it -- is consciousness, the ability to see "the miraculous density of day's data structure" in "a place wide enough to house human restlessness."

Although sometimes heart rending, particularly in the Beirut sections, "Plowing the Dark" is by and large a work of great charm animated by the simple joy of making things. "You type some words," says Stevie, a poet turned systems engineer, "the inner name of the thing. You describe how you want it. You build a topical outline of its behavior. Then you run the description, and there the idea is. Actual, working "

I don't suppose any real VR lab ever tried to grow Rousseau's vegetation, or to rebuild Van Gogh's room in Arles and open the window's heavy shutters. But what a lovely thought, and what lovely language Powers bends around the imagined programming tasks:

Collision had already cost the team a tidy sum of man-months. It wasn't enough for a garden-variety mushroom sprouting in the Cavern simply to look like one. Even a toadstool needed heft and weight and resistance. A simulated object had to bend or droop or bruise or any of several dozen other verbs that real things did when bumped up against  Various variables toted up mass and speed and English, calculating the thresholds between bounce and break, between shatter and slide and spin.

Think of the old Windows screen saver that sets two delicate polygons rotating in space as their angles narrow and widen and their colors traverse the spectrum. And then imagine a blooming, buzzing world in three dimensions, every object enabled to act to the extent of its attributes -- its mass, its speed, its  English. Powers' fertile, restless English is endlessly plastic, infinitely ready to reshape itself around whatever world he's exploring at the moment. Wildly fecund in "The Gold Bug Variations," nearly desperate in "Operation Wandering Soul," his language here is as hard and bright as the syntax of Java or C++.

A smaller-scale work than, say, "Gain," "Plowing the Dark" remains rooted in its historical moment and insistent on human perception as the measure of things. Although imbued with the horrors of war and the unholy technologies of unmaking the world, it feels almost optimistic in its resolution, refreshing in its evocation of a time less cyberselfish than our own. It's a chamber work, really, this meditation on rooms and other spaces, this smart, sweet, harrowing novel that reminds us how much the human prospect depends upon the homes -- virtual and otherwise -- that we build for ourselves on Earth.