To mark this month’s fiftieth anniversary of the Beatles’ ninth album, “The Beatles”—universally known as the White Album—several new expanded and enhanced editions are being released this week. These new versions were created under the supervision of Giles Martin, the son of the album’s original producer, George Martin. As was done last year with “Sgt. Pepper,” the new editions contain, along with a wealth of archival recordings and other material, a brand-new, digitally remixed presentation—a laborious retrieval and reassembly of the contents of the original multitrack master tapes, with a comprehensive scope far beyond that of all previous remasters and releases. The result reveals what might be called the greatest record ever made, not only in terms of its innovation and its strange, impenetrable, endlessly suggestive beauty but also because of its place at the apex of the Beatles’ career and its role as an aesthetic keystone for nearly all the rock-and-roll recordings that have followed.

Upon returning to England from Rishikesh, India, in April, 1968, John Lennon and George Harrison stripped and sanded the psychedelic paintwork off of their Gibson J-160E and Casino guitars; Donovan, one of the many musicians who had accompanied them to the Maharishi Mahesh Yogi’s ashram for an advanced transcendental-meditation course, had told them that this would improve the sound. “If you take the paint and varnish off and get the bare wood,” Harrison explained later, “it seems to sort of breathe.” This stripping away of psychedelic symbolism was part of a larger campaign that the band undertook to remove the layers of Beatles mythology, habit, and convention that had accumulated since their beginnings, as Liverpool teen-agers—before Germany and America, before Astrid Kirchherr’s arty portraits had fetishized their mop-top haircuts, before Ed Sullivan and “A Hard Day’s Night,” and Shea Stadium, and the rest of it. Psychedelia, and the Beatles’ influential participation in it, had peaked with the release of their landmark 1967 album, “Sgt. Pepper’s Lonely Hearts Club Band,” the surrealist tracks on which had beguiled the world and, many said, inspired the Summer of Love. The American political theorist Langdon Winner observed, “The closest Western Civilization has come to unity since the Congress of Vienna in 1815 was the week the ‘Sgt. Pepper’ album was released. . . . At the time I happened to be driving across the country on Interstate 80; in each city where I stopped for gas or food—Laramie, Ogallala, Moline, South Bend—the melodies wafted in from some far-off transistor radio or portable hi-fi. It was the most amazing thing I’ve ever heard.”

“Sgt. Pepper” had its detractors: the British critic Nik Cohn complained that “it wasn’t much like pop. . . . It wasn’t fast, flash, sexual, loud, vulgar, monstrous or violent. . . . Without pop, without its image and its flash and its myths, [the Beatles] don’t add up to much. They lose their magic boots, and then they’re human like anyone else; they become updated Cole Porters, smooth and sophisticated, boring as hell.” “ ‘Sgt. Pepper’ is called the first concept album, but it doesn’t go anywhere,” Lennon observed years later; the next record, he believed, would be a chance “to forget about ‘Sgt. Pepper’ and get back to making music.” Brian Epstein, the record-store manager who discovered and managed the Beatles, had died unexpectedly in August of 1967; without Epstein, without the pressures and demands of touring (which they had stopped after 1966), and having reached this apparently historic peak of artistic and worldly success and fame, the Beatles were finally free from all constraints and paternal influences. When they eventually soured on meditation and the ashram culture—as Lennon would relate in his savage renunciation, “Maharishi” (eventually renamed “Sexy Sadie”)—there were, finally, no father figures left at all.

The sojourn in India, led by Harrison, had been an attempt to start over, accelerating the stripping-away process that would culminate in their most ambitious musical project. “I remember talking about the next album, and George was quite strict,” McCartney said. “He’d say, ‘We’re not here to talk music—we’re here to meditate.’ ” But the songwriting—inspired by the locale, the Maharishi’s lectures, and, especially, the impromptu celebrity community there—had accelerated, and Lennon soon sent a postcard to Ringo Starr (who had tired of meditation sooner than the others and returned to London), saying, “We’ve got about two LPs worth of songs now, so get your drums out.”

The Beatles’ transition from performance to studio work, and the atomized process it allowed and encouraged, now reached its apotheosis. George Martin, who was the Beatles’ Maxwell Perkins, producing all but one of their albums, explained, “The ultimate aim of everybody [had been] to try and recreate on records a live performance as accurately as possible. . . . We realized that we could do something other than that.” “Sgt. Pepper” is a simulacrum of a performance, the concert crowds replaced by recorded cheering, but the new record would remove this narrative crutch. Also gone was the picturesque subject matter: the street landscapes and polite courtships, the elderly couples and fumbling suitors and office workers trapped in suburban patterns, intruded upon by surrealism, like figures in Magritte paintings. In their place would be a clear, raw vision of an unsafe, chaotic world.

As McCartney recounts in his notes accompanying the new edition, “We had left Sgt. Pepper’s band to play in his sunny Elysian Fields and were now striding out in new directions without a map.” The Abbey Road studios became the Beatles’ safe space, where, as McCartney writes,“the tensions arising in the world around us—and in our own world—had their effect on our music but, the moment we sat down to play, all that vanished and the magic circle within a square that was The Beatles was created.” Fitting together like a novel or a painter’s canvas, “The Beatles” abandons psychedelia for a more sophisticated set of aesthetic principles, embracing the avant-garde: Lennon had begun spending time with a new girlfriend, the conceptual artist Yoko Ono, who had been associated with the Fluxus movement, a group that pledged in its manifesto to “PURGE the world of dead art, imitation, artificial art, illusionistic art, mathematical art . . . promote a revolutionary flood and tide in art, promote living art, anti-art, promote non art reality to be fully grasped by all peoples, not only critics, dilettantes and professionals [and] Fuse the cadres of cultural, social & political revolutionaries into united front and action.”

“The Beatles” is as much a concept album as “Sgt. Pepper,” and the concept is, again, right in the title: a top-to-bottom reinvention of the band as pure abstraction, the two discs, like stone tablets, delivering a new order. (“By packaging 30 new songs in a plain white jacket, so sparsely decorated as to suggest censorship,” Richard Goldstein wrote in his New York Times review, “the Beatles ask us to drop our preconceptions about their ‘evolution’ and to hark back.”) The songs progress through a spectral, mystical, and romantic dimension, the soundscape itself becoming fluid and associative. The Beatles’ ability to conjure orchestras and horns and sound effects and choirs out of thin air imbues the tracks with a dream logic. The juxtaposition of order and disorder, of the ragged and the smooth, of the sublime and the mundane, of the meticulously arranged and the carelessly misplayed, provides what the critic John Harris called “the sense of a world moving beyond rational explanation.” The music seemed to absorb the panic and violence of 1968, the “year of the barricades.” As the Sunday Times critic commented, “Musically, there is beauty, horror, surprise, chaos, order; and that is the world, and that is what the Beatles are on about: created by, creating for, their age.”