The movers deposited the books on the first floor and the compact discs on the third floor, exactly the opposite of what they'd been asked to do. Shifting them meant an operation of Rubik's Cube complexity, carrying boxes sideways through small canyons created by precipitously high piles of cartons. Much sweat, some rugged cursing, and a small epiphany later, some 200 boxes had changed places.

I didn't mind moving the books upstairs, but I deeply resented moving the accumulation of compact discs to the ground floor. There are some 8,000 of them now, a small collection by true fanatic standards, but enough to be a logistical nightmare. Where to shelve them? How to organize them? Milk cartons and pine boards on bricks ceased to be practical years ago. And alphabetizing groaned into uselessness as an organizational principle once the uncategorizables--collections of multiple composers and multiple performers--numbered more than a few dozen.

Moving the books meant moving a collection, something very different than moving a stockpile of CDs. Collections are individual, they represent choices, show the trace of past curiosity and ongoing obsessions. When collectibles, and books especially, age, they carry a kind of personal, immanent history. CDs, on the other hand, merely accrue, pile up, accumulate and, perhaps, deteriorate. Like the laser that scans them, time and experience never touch the CD.

It's easy to hate compact discs. Since their arrival on the market in 1983, curmudgeons and Luddites have griped about their sound quality and design. Dry acoustics, digital sterility, unreadably small program notes, minuscule cover art, easily broken jewel boxes, nail-breaking plastic anti-theft packaging and so on. Yet CDs revolutionized--some might say steamrolled--the world of recorded sound with astonishing rapidity, which only further irked traditionalists and audiophiles. Within five years of their introduction, CDs were outselling LPs. The griping about their omnipresence and inadequacy was reminiscent of that surrounding a certain president: They were extremely successful, despite what some felt was an appallingly high fidelity problem.

The debate about analog versus digital sound defined the era of the CD, and continues to this day in small backwaters habited by connoisseurs. The analog sound of the LP and tape was authentic sound, the kind of sound a small, homey farmhouse with a bright fire and the smell of roast goose might make. Digital sound was modern, hard-edged sound, glass and steel and plastic, mechanized and inhuman. Analog had patina. Digital was stainless steel.

To an extent, this wasn't an unfair characterization of the early days of digital sound. But it was a distinction primarily available to those who could afford top-of-the-line equipment. For most listeners, the CD was unquestionably an improvement over the scratches and pops of the untrustworthy LP. This critic, who began serious collecting only shortly before the introduction of the CD, was pleased to find a format impervious to peanut butter and jelly.

Move a few thousand CDs on a day pushing 100 degrees, and the old debate between analog and digital sound seems irrelevant to the grand historical narrative of the format. CDs are just now finishing their historical purpose, a role that was a bit like John the Baptist's, preparing the heathen for a new era. That era will be defined not by sound quality (which will no doubt continue to improve until it hits the brick wall of the human ear's innate inadequacy), but by accessibility, speed of access and ease of organization.

Things that at first seemed like insignificant conveniences of the new format--tracking and indexing, which made it possible to find one's place in a piece of music instantly--may be seen as precursors of how the CD has changed, and will continue to change, listening habits. Tracking broke down the organic notion of the LP as a concert or recital of sorts; with LPs, one could find a particular cut, but at peril to the vinyl surface, the stylus and one's nerves. The format encouraged listening through a half-hour's worth of music, hearing arias or movements in their original order, in their original musical context. With CDs, however, one could listen with precision to discrete bits, repeatedly if desired and without damage to the disc.

The CD also changed buying habits. Perhaps most telling is the early marketing slogan of the Dutch-based Philips company, which pioneered CD technology. "Perfect sound, forever," they said. "Forever" is the key word. With guarantees of unprecedented longevity, investment in CDs was a long-term proposition. This confidence in the format encouraged collectors not only to stay current with new recordings and artists, but also to replace aging LPs with CD copies. By 1985, recording companies were beginning to oblige the demand for back catalogue, reissuing classic recordings in ever greater numbers on CD format.

Watch the headlines today, however, and it's easy to wonder whether such diligent library building will soon be all for naught. The recording industry is increasingly turning to the Internet to market its product; so far it is concentrating on services like Amazon.com that use the Internet like an old-fashioned catalogue, sending the actual product through the mail. The next generation of digital download technology is already upon us, however, and it will make the relatively lightweight and compact CD seem bulky, and perhaps unnecessary, as listeners download music directly into their computers or specialized players. Moving the CDs, unpacking and refiling them, cursing their numbers, their cumulative weight, and the responsibility of storing them, I was struck by the terrifying thought that these thousands of little plastic Frisbees will all be trash within a few years.

Two forces are coming together to ease the CD into the rubbish bin of history. Technology that allows the digital information on a CD to be compressed into ever smaller spaces is already hitting the market. And the Internet, which is benefiting from faster download times and improved compression technology, is offering access (not always legally) to music online. Together, these forces point the way to a new generation of universal musical access, through the home computer, with limitless unforeseen possibilities: music on demand, perhaps like pay-per-view television, with sophisticated search engines to locate even the most obscure historical performances.

But the glut of possibilities and options that distinguishes the new entertainment age also has an enervating effect. Think of the way cable and satellite television, combined with the remote control clicker, have changed the way we watch television. Mustering the attention span to actually watch a single program of an hour's length becomes increasingly difficult. The medium encourages promiscuous viewing. The same phenomenon, applied to classical music, won't encourage the appreciation of Mahler or Wagner.

The new entertainment age also places much greater weight on the choice of what to watch, or listen to. Choosing a program, or a recording, isn't simply a matter of deciding what one wants to hear. Equally important is being sure that there isn't something better just around the corner. This mixture of finickiness and impatience, which can paralyze people in a singles bar, can be paralytic to listening as well. It makes listening more selfish, more about tailoring one's aural space to fit a particular fleeting mood or desire. The music becomes almost secondary, a mirror of one's self at that moment, rather than a challenge, something to be confronted and actively studied.

For as long as music, or words, or images, could be found only in an object--printed music or recordings, books or paintings--their appreciation required an investment. Not just financial investment, but an intellectual and emotional investment. This naturally limited the breadth of what we knew and cared for, while very often increasing the depth of appreciation for any particular symphony or poem. Simple listening habits--Bach partitas with the morning coffee, zarzuela to prepare for housecleaning--which have long brought pleasure to people, were based on that investment. Consider the listening party, at which rarities from one's collection are trotted out for collective enjoyment. A major part of the pleasure was sharing, which presupposes a kind of unique ownership--having found something obscure, invested in it by purchasing it and caring for it, and further invested in it by learning its unique delights. Will this gentle, human joy survive universal access, in which laying claim to a particular oddity is an increasingly abstract notion?

More than 60 years ago the German Marxist and cultural historian Walter Benjamin wrote two essays--"Unpacking My Library" (1931) and "The Artwork in the Age of Mechanical Reproduction" (1936)--that explored the way that possession and reproduction influence our relation to cultural objects. Benjamin was a conflicted Marxist, bemused with his own fetishization of books, fascinated by the possibilities and problems of large-scale reproduction of images (and music). In many ways he anticipated the crossroads we have reached today, where it is unclear whether the leveling forces that make art available to the masses will lead to greater appreciation, or greater irrelevance of art itself. He also suggested the concept of the "aura," the particular uniqueness of the artwork that is dissipated in the process of multiple reproduction and dissemination.

Throughout the history of recording, critics have debated whether recordings compete with or enhance live performance. As music lovers enter the era of universal musical access, will the dynamic between the profit-making recording industry and the nonprofit world of live performance change? Ever since the horse-and-buggy days of wax cylinders, improvements in the world of high fidelity have been aimed at competing with the authenticity of live performance. Yet despite the brilliance and accuracy of digital sound, the live concert has survived. It has survived because it still has an aura. It means something to say you were there, you heard Arthur Rubenstein unfolding the Chopin nocturnes like black velvet.

Pessimists may leap to the conclusion that universal access will be the last nail in the coffin for live performance. Optimists might look to the revenge of the aura for hope. As the new entertainment age replaces traditional listening with fractured, dispersed listening, nostalgia for the concert may have its due.

Classical music radio, which has steadily descended into a morass of Baroque wallpaper music and top-10 symphonic hits, still has a strange appeal. The radio chooses for us, dictates the listening time, the order of the music, the performers who play it. By limiting our choice, it focuses our attention. It chooses for us music that we may think we don't want to hear, but enjoy nonetheless. And to a certain degree, it creates a community of listeners who can ask each other, Did you hear that Berwald symphony on WETA last night?

These are all things that the concert does very well. The concert offers an escape from promiscuous listening, removing choice and restlessness, and forcing us back on the cultivation of attention, and memory. If universality of access is enervating, the concert may well be a redemptive, disciplined pleasure, returning us to the authenticity of the original as the collective accumulation of reproduction becomes unmanageable.

That is, of course, until the day when even live performance is instantly and universally available, archived as it transpires, preserved perpetually in a simulated world that is indistinguishable from the real. And what then? Will there be any hope of an authentic musical experience?

Then, perhaps, the only realm of truly unreproducible, truly private musical experience will be the music we make simply for ourselves. To ride out the next wave of technology, perhaps we all need to learn to play the piano. Or the flute--it's easier to move.