It is spring 1966, and the Beatles are ensconced in London’s EMI Studios, where they have embarked upon their latest manipulation of time. The Christmas season just passed had seen the release of the band’s sixth album, Rubber Soul, a game-changer of a disc that wedded American rhythm and blues to English folk music, as if the two genres were meant to go together all along. The Beatles, as the popsmiths-cum-pied pipers for teenyboppers, the lovable lads behind A Hard Day’s Night, were no more. Their middle-career era of high-toned, big boy art had commenced.

Rubber Soul continued to dominate the charts that spring. It featured organic sounds sourced from the streets of the city and countryside fields where one might have pictured John Clare wandering, but the Beatles, being the Beatles, were now moving entirely beyond Rubber Soul’s rustic-tinged soundscapes, as if such a masterwork were a mere digression in their journey towards something bigger, something better, something more “next,” if you will.

In this case, that would be the finest album of their career, and conceivably the finest rock and roll record ever made: a 14 song affair clocking in at under 35 minutes with a bad pun serving as a title: Revolver. For what do records do? Revolve. And this one was going to feel like it did so more than any that had come before.

People tend to forget how short the Beatles’ career was as a record-making collective: a mere seven years, from Please Please Me in 1963 to Abbey Road in 1969. Their pace was extraordinary, with single calendar years featuring the completion and release of two LPs and three singles, the latter rarely sourced from the former.

Mix in tours, spates of recording sessions for the BBC, film work, all manner of personal appearances, and you start to wonder how on earth four men were able to leap about from style to style, inventing some in the process, serving as the definitive version of one kind of band in June, say, and then another in July.

Revolver, though, which would be released in August, was the ultimate shape-shifter document, for having just infused the ears of the world with an album that was all green and brown tones, with a wafting air of cannabis throughout, the Beatles went interplanetary.

There is no record that sounds remotely like Revolver, and certainly no Beatles record. John Lennon had just reached a compositional career high point on Rubber Soul with songs like “Girl,” “In My Life,” and “Norwegian Wood (This Bird Has Flown),” and now it would his partner Paul McCartney’s turn to hit the apogee-mark.

Lennon was writing on the guitar at the time, as he always had, but with a greater penchant for distortion and overdubbed layers of guitars that came at you in metallic waves, as if borne in from an Arthur Clarke novel. McCartney, meanwhile, had become quite the aesthete in London, living in town and taking in the theater, films, anything, as the Jefferson Airplane would later sing, with which he could feed his head. He was also, for the first time, writing on the piano, and it is from this yin and yang of two geniuses composing about as well as ever, on somewhat oppositional instruments, that those spring 1966 sessions were setting Revolver up as something of, well, an absolute mother of an album.

George Harrison, too, was excelling as a writer, and it was his “Taxman” that was granted the prize position as album starter. The Beatles didn’t muck about with what they chose to begin and, more important, conclude their LPs. As with “I Saw Her Standing There,” the song that launched their first record, “Taxman” features a cod count-in, with Harrison, in a sardonic, almost glib voice, intoning a flat “One, Two, Three, Four,” as the real count-in is shouted out beneath him, and away we go into Future Rock.

The lyric is a diatribe against the English taxation system, but it’s almost immaterial, given what is at play sonically, as the Beatles, clearly, have a new weapon they hadn’t before. McCartney takes a guitar solo where normally Harrison would, a fury of virtuosic playing to make Jimi Hendrix sit up and take notice, and few, if any bands, have ever been tighter. As players, these guys are all coming into their own. But there is no more important instrument on Revolver than the studio itself.

This was a first. You hear it right away in the texture of McCartney’s bass. A bass is not meant to sound this rounded, as if it were an instrument you could isolate in any given track, and study as a composition unto itself. Producer George Martin, always a man willing to try an idea, is now clearly abetting two songwriters who were coming up with a ton of them in terms of the new sounds they’d like to try and get, thus bestowing each of their songs with an extra kick towards places no one had gone before.

For McCartney, that involved working with engineer Geoff Emerick on making his bass sound like a rumble of low-toned, especially melodic guitars, knitted together in the soundscape. Lennon, meanwhile, was talking of being tied to cables and maneuvered around the room so that his vocals would sound preternatural, and tasked Martin with some requests that would have required drilling holes in his neck and inserting electrodes. The Beatles-go-Frankensteinian.

Lennon is always considered the band’s maven avant-gardist, but that’s misleading, and the point of no return moment in the Beatles career, as far as advancing on the realm of psychedelia goes, comes with the second number, McCartney’s “Eleanor Rigby.”

The tale of a lonely spinster, and the lonely people in her life, such as it was, is seen “wearing a face that she keeps in a glass by the door.” Well then. You didn’t get this on Rubber Soul, or anywhere else. Here the sound is clean, string-laden, the stuff of Edwardian minstrels leaving the band back home and tending to a respectful threnody.

McCartney explores more iterations of this sonic mood, though with more joy, throughout Revolver. “Here, There and Everywhere” is the finest love song of his career, a quiet, sunlit number, with degrees of affection becoming more pronounced in charming modulations. “For No One,” a piano track with a French horn solo by Alan Civil, is the emotional flipside of “Here, There and Everywhere,” and yet strangely uplifting as a song lamenting “what ifs.” McCartney is commanding melodic possibilities at the loftiest of levels, and you sense that there is nothing he can’t do with it. Including, even, making you look forward to a bit of heartache.

Lennon, meanwhile, is in guitar overdrive, and having fun with it, like on the electric guitar concerto grosso, “And Your Bird Can Sing.” A rehearsal version on the second Anthology finds Lennon and his buddy Macca unable to control their giggles as they sing along. The Beatles wouldn’t have this much fun on a session again, and they needed that work-friendly affability in some regards, as this music was going to some dark places—dark, in many ways, because of the uncertainty they represented for a person like Lennon.

His home recording of “He Said He Said”—which would grow up to become the Revolver track “She Said, She Said,” about a bad LSD experience and contemplating one’s inevitable demise—is like a musical version of venturing into the previously unknown, half expecting something fearful, half expecting a kind of deliverance. A toe in psychotropic waters. In moments of self-doubt, Lennon always turned to the guitar, and the “She Said” riff is an angular, snaking thing, with Ringo Starr’s drums pawing at the song.

Starr gives a masterclass in drumming throughout, and you get the sense that his flexibility as a player helped free up what the band was willing to try. He’s in a proto-funk groove on McCartney’s “Got to Get You Into My Life,” which features a Harrison guitar fill, lasting only a couple bars, but counting among the four or five best things he ever played.

Lennon’s “I’m Only Sleeping” is its own proto affair, a somnambulistic mini-dry run for “Strawberry Fields Forever.” Childhood mattered much to Lennon, and as an adult his best songs were written through a process of courage to trust and submit to that capacity of wonder from more innocent times. On that score, there is McCartney’s “Yellow Submarine,” rounded out with Lennon’s hilarious off-mic mischief-making, a children’s song of sorts, but one so teeming with imagination that it’s akin to something Narnia-esque—in other words, both for the kiddies, and for the most adult of the adults.

McCartney’s “Good Day Sunshine” is another instance of piano-centric brilliance. Whatever the man wished to turn his hand to during this period was whatever he was shortly going to master. We think of him now as all cuddly and belting out the latest chorus of “Hey Jude” on the northern side of seventy, but this McCartney was a fiery innovator. And yet, for all of those new compositional approaches by the eventual Sir Paul, it is Lennon’s “Tomorrow Never Knows” that is Revolver’s essence encapsulated in a single track.

There were, of course, no electrodes, but George Martin and crew came up with something dubbed ADT—automatic double tracking. And it is that that makes Lennon’s voice sound, to paraphrase his own words, like he’s a thousand monks chanting on a hill.

The song was alleged to originally be titled “The Void,” and on the first take of it, also available on Anthology II, Lennon might as well be singing from inside a chambered nautilus as the Reaper beats time on the outside of the shell.

This is a death work, in a sense, but there’s something uplifting for all of the freaked out, full-on LSD madness, with those crazy cries like crows loosed from an overheated Shakespearean dream sounding again and again. You might think of it more like a transposition from one place that was quite good, to another that might be better yet, if you’re game for the leap. As the Beatles themselves were, of course, when they deemed it time to go revolving.