John Martyn was, in every way, a hard man to pin down. He was a gregarious, rambunctious guy who loved to booze and brawl—he beat up Sid Vicious after the punk singer insulted him during a poker game. Equally talented as a singer, songwriter, and guitarist, he wasn’t quite virtuosic at any one of these things. He was an integral member of the flourishing and shaggy British folk movement of the late 1960s and early ’70s, yet his most acclaimed music can’t really be characterized as “folk” at all. His plainspoken lyrics aren’t as idiosyncratic as Richard Thompson’s mordant drama or his close friend Nick Drake’s tender eloquence, to name a couple of his contemporaries. So what makes Martyn special? It’s his unmatched ability to tap into a specific aspect of music-making, one whose cultural currency has peaked in recent years. Martyn was the master of vibes.

To pedants and spoilsports, “vibes” is either a meaningless word or an expression of meaninglessness, a rhetorical crutch of the inarticulate to convey aesthetics, charisma, or energy. But vibes are real. As professor Tom F. Wright argues in The Atlantic, the term has roots in the 19th century, “older esoteric traditions that described social relations as ‘vibratory,’” later revived via the “good vibrations” of the hippies in the ’60s. For Martyn, “vibes” undoubtedly describes an ineffable mood or sensibility, a “tune in, turn on, drop out” mindset undergirding a preternatural cool. Yet it’s also music full of actual vibrations—keyboard twinkles, frenetic woody basslines, scuttling percussion, and reverberating cyclones of guitar strums, unmoored and seemingly levitating in the ether, coiled by a burly, warm voice slurring words into splatters and smears.

It’s a testament to Martyn’s technique and fundamental training that this circuitous architecture never sounds remotely off-putting or inaccessible. In his music you can hear the autumnal warmth of Nick Drake, the soul-searching intensity of Van Morrison, the kaleidoscopic exploration of electric Miles Davis, and as Martyn frequently acknowledged, the clacking, searing earth-fire of Pharoah Sanders. What all these artists share is an astral perspective, a supernatural ability to divine music that soars in atmospheric planes. For Drake it was an Orphic sense of the elysian; for Morrison it was repetition as a means of attaining the mystical. Yet where Drake and Morrison projected inward, and where Davis and Sanders billowed outward, Martyn’s music seems to move from the inside out, or omnidirectionally. But it’s not “free”—it has structure and melody, intimacy and soft edges. It possesses a quality that is hard to isolate or map. It’s just… vibes!

“Vibes” is what you might say out loud when you hear the first five seconds of Solid Air, Martyn’s fourth and greatest solo album, and not just because there’s a literal vibraphone. It’s all about the atmosphere, the vibraphone rippling like pebbles on a nighttime lake. And what’s remarkable is something that was Martyn’s superpower: how sounds refract his emotions and subject matter. On the opening title track, the wafting vibraphone emulates the depressive fog of the song’s subject. “You’ve been taking your time, you’ve been living on solid air,” Martyn sings, puffing out each word like smoke rings. “Solid air” perfectly describes the invisible force of depression, but it could also represent a narcotized stupor, or the paranoid fringes of psychedelic exploration. At the end of alternating verses, Martyn intones, “Don’t know what’s going wrong in your mind/And I can tell you don’t like what you find.” It might be outreach to a host of people: someone who’s suicidal, someone on a bad trip, a drunk, maybe even all three.

Unfortunately, we know whom it’s about. Martyn first sang the vocal melody to Paul Wheeler over the phone, after visiting their mutual friend Nick Drake in 1972. “It was done for a friend of mine, and it was done right with very clear motives,” Martyn later said. It was shortly after Drake had released his final album, Pink Moon, and withdrew deep into the cobwebbed shadows of antidepressants. Martyn and Drake were an unlikely pair—the former bellicose and working-class, the latter moody and patrician—but they shared a love of substances, guitars, and dark humor. And they were both noticeably sensitive.

Martyn’s songs are emotionally sensitive, yet it’s his musical sensitivity that’s extraordinary. “Solid Air” bears the quiet hush of folk, but also the interplay and environs of jazz. Fairport Convention’s Dave Mattacks lightly taps out a drum beat, Pentangle’s Danny Thompson juxtaposes Martyn’s guitar with acoustic bass jabs, and session saxophonist Tony Coe intermittently blows out street lamp-lit sax lines. There’s a forward momentum, but it’s floating, guided by internal logic rather than chord progressions or rhythm, not unlike Pharaoh Sanders’ “Astral Traveling” (which “Solid Air” is habitually compared to, even though Martyn hadn’t heard it yet). Tristan Fry’s vibraphone was defective, and to get the undulating sound on “Solid Air” he had to employ a process called “finger-damping,” where you have to stop each note with your hand before batting the next one. The musicians had to be legitimately sensitive to their instruments and to each other, a manifestation of a song in which the protagonist is trying to be sensitive to his friend’s plight. Which played out in real life: Martyn never told Drake or anyone else who “Solid Air” was about until after Drake’s death.

Solid Air is sometimes portrayed as an album about Nick Drake, when it’s really all about Martyn. And aside from the spectral “Man in the Station,” none of the other songs on Solid Air resemble the title track. Martyn see-saws between folk-jazz, straight folk, space-blues, jazz-rock, brooding folk-blues—but rarely a melding of all of it. Producer John Wood also recorded Pink Moon—the complete opposite of Solid Air in its austere and predetermined manner—and the one thing they have in common is a consistent tone. On Solid Air there’s anger, confusion, joy, desperation, and sadness, yet it never sounds chaotic. Throughout, the mood is somewhere between a dinner party and a seance. It’s the imprint of a man who was externally cheerful and internally tumultuous, a mess of contradictions masked by charm and talent.

Solid Air was released in February 1973, when Martyn was just 24, after he broke off one engagement, signed a record contract, watched his career stall, fell in love with another woman, got married, adopted her son, formed a duet with her, fathered another child, and left her to raise them while he tore off on long tours. Reckless, restless, and selfish, it was a far cry from the Martyn of 1967, a cherubic 18-year-old playing winsome folk ditties at the Folk Barge, an authentic Dutch barge with blacked-out windows bobbing under the Kingston Bridge in London.

The man born Iain McGeachy was a Glaswegian with boyish good looks who immediately stood out in the early heyday of British folk. Initially spellbound by Joan Baez’s spindly fingerpicking and Davy Graham’s sideways approach to folk, McGeachy was a prodigal pupil of the Scottish blues guitarist Hamish Imlach. He developed a right-hand movement that combined elegant fingerpicking with percussive and horizontal strumming. At his agent’s suggestion, McGeachy changed his name to “John Martyn” because it was easier to pronounce.

From the moment he heard Martyn, Island Records owner Chris Blackwell astutely identified him as a jazz musician rather than a folkie, a person who “didn’t follow the normal rules of music … it could be anything, you never knew where he was going.” He was the first white solo performer Blackwell signed to Island, which at the time was, in Martyn’s words, “a spurious label; they used to release dirty noises and stuff called Aphrodite Unleashed or something … any kind of record that would make money.”

If Martyn’s approach tilted more toward jazz than folk, it was hard to decipher on his 1967 debut, London Conversation. At this early point, Martyn was clearly enunciating his words and unspooling slight ditties about “magic dancing wood” and “elves and pixies” on solo acoustic guitar, conjuring the papery whimsy of early Donovan, even when he was covering harder-edged blues standards (“Cocain”) or jamming on a sitar (“Rolling Home”). Still, Island was starting to get some juice and Martyn had some hustle, and by 1968 he had moved up to a weekly residency at the ultra-hip folk club Les Cousins. In the same year, Martyn released The Tumbler, where the jazz influence first peeked through, with flautist Harold McNair circularly fluttering on four tracks. Despite the flute, The Tumbler, like its predecessor, didn’t sell much, but both albums were recorded so cheaply that Blackwell kept him on the label.

Toward the end of 1968, Martyn met Beverley Kutner, a fellow semite and up-and-coming singer in the folk scene. They married less than a year later, Beverley took Martyn’s fake last name, and they became a musical duo. At the time the Band were at their musical and cultural peak, and while their debut Music From Big Pink made a lasting impression on John, he was also grabbing inspiration from a host of sonic explorers: the gurgling loops of composer Terry Riley, Joe Zawinul’s chasmic keyboard work with the jazz-fusion supergroup Weather Report, and especially Pharoah Sanders’ spiritual-jazz totem Karma. Martyn would play the latter record endlessly (instigating a short-lived attempt to learn saxophone) and became fascinated by polyrhythms and modulation. And for the first time, he began to think of his voice texturally, an esophageal incarnation of Sanders’s horn.

Though by all accounts John dominated the sessions for the two albums he made with Beverley—Stormbringer! and The Road to Ruin—both LPs feel restrained, an audible insinuation of something he would admit later, which is that his spirit belonged under his total control. In Danny Thompson, Martyn met a collaborator, both offstage and on, who indulged his wild and self-immolating side. A fellow boozer and rabble-rouser, Thompson exclusively played a stand-up double bass, infusing jazz into the otherwise hard folk of his band, Pentangle. He and Martyn entwined in a whirling tango of flittering string-play, a style they referred to as “making it up as you go along … without knowing the notes.”

Martyn also discovered a robotic companion: the Echoplex, a tape-delay machine that records a note or chord and reproduces it as a simulation of an echo, like a heartbeat turning into a pulse. By plugging his acoustic guitar into effects pedals and the Echoplex, Martyn realized, as he later recalled, “You chop in between rhythms, and you can choose your own timings because it’s completely elastic…. I just like the idea of making a machine human in that way, and I like impressing the humanness of yourself onto a machine rather than the other way round.”

Acoustic/electric, human/machine, solid/air: Martyn’s music is immersed in binaries and dialectical resolution, a constant quest for peace amid conflict. The first intimation of these divisions is on 1971’s Bless the Weather, after he dissolved his duo with Beverley. Though Thompson played on The Road to Ruin, Bless the Weather is the moment when his work with Martyn flowered into a symbiotic partnership. “Head and Heart” explicitly lays out a dichotomy Martyn would address throughout his career, its chorus a plea for a complete love (“Love me with your head and heart/Love me with your very self/Love me with your head and heart/Love me like a child”). But it’s on “Glistening Glyndebourne” where Martyn really started to push his sound into more open-ended territory, a wordless, six-and-a-half minute free-folk excursion laden with Echoplex-sluiced guitar.

By the summer of 1972, when Martyn began the sporadic sessions for Solid Air, he was intent on exploring a post-folk style. Initially, he worked with, in his words, “some very heavy super-starry people,” but ended up hating what came out of it. As he was about to embark on a U.S. tour at the beginning of 1973, Island needed an album to promote, which left Martyn with less than two weeks to record something. He assembled a core unit of himself, Thompson, and Free keyboardist John “Rabbit” Bundrick, with Mattacks on drums and fellow Fairport member Dave Pegg on occasional electric bass.

The aural possibilities of “Glistening Glyndebourne” abound on Solid Air’s “I’d Rather Be the Devil,” a cover of Skip James’s “Devil Got My Woman.” Where the original sounds like a dusty transmission from the distant past of Delta blues, Martyn launches James’ version on a trajectory toward a cosmic future. He directed Mattacks to “think free-form Elvin Jones,” delivering a caterwauling jazz foundation to rat-a-tatting guitar, Pegg’s moody playing, and Bundrick’s chunky clavichord accents. Martyn incomprehensibly growls James’ words, and at 2:20 the singing stops, with the band locking into a groove that sets you up for a blues jam. But a minute later something unexpected happens: The rhythms vanish and Pegg’s electric morphs into Thompson’s stand-up bass, conjoining with Martyn’s flickering guitar for an ethereal improvisation, halfway between the celestial heights of Miles Davis’ In a Silent Way and the infinite murkiness of Bitches Brew, for three transcendently blissful minutes.

The closest parallel to “I’d Rather Be the Devil” is “Dreams by the Sea,” a sunglasses-required funk track that’s like Curtis Mayfield by way of the south British coastline. Martyn’s music is filled with references to water, not just in its sound but in imagery throughout his discography. It might be due to Martyn moving his family to a waterfront house in Hastings, a small town along the English Channel. But if the title of “Dreams by the Sea” connotes domestic beatitude on the shore, the menacing tone and fearful lyrics indicate dissatisfaction with his home life. “Dreaming you’ve got a lover/Dreaming I got another/Dreaming that there’s a killer in your eyes,” Martyn sings near-frantically, pointing toward a future of self-sabotage. And then release—the last 30 seconds strewn with nothing but Bundrick’s sporadic, starry Rhodes.

Bundrick appears on half of Solid Air’s songs, and his keyboard emits an intoxicating shimmer imparting undercurrents of druggy serenity and anxious self-doubt. Side A’s “Don’t Want to Know” and Side B’s “The Man in the Station” are practically mirror versions of each other, jazz-rock saunters through the most cautionary doors of perception. In “Don’t Want to Know” Martyn begs not to be betrayed by his worst impulses: “I don’t want to know about evil/Only want to know about love,” he repeats mantra-like on the chorus. And in “The Man in the Station” there’s already the implication that Martyn has fallen prey to his demons, with a faint glimmer of the good man inside: “There’s a face in the mirror that’s showing the strain/There’s a woman in the dark that’s standing apart/There’s a love in the man and it’s breaking his heart.”

Martyn had yet to completely abandon folk. “Go Down Easy,” a duet with Thompson, might be the best Neil Young song not written by Neil Young, with a guitar line reminiscent of “Old Man” and Martyn singing in high falsetto. “Old Man,” however, is a yearning recognition of the lineage of fatherhood, whereas “Go Down Easy” intones connubial intimacy with lecherous seduction, an admission that love is always in danger of lust. The lyrics feel like a married couple nuzzling each other before bed—“You curl around me like a fern in the spring/Lie down here, let me sing the things you bring/And we can go down easy”—but Martyn sings it with the seductive boldness of hitting on someone at a bar.

It’s the two most well-known tracks on Solid Air, the jaunty “Over the Hill” and the unadorned “May You Never,” that show Martyn was still drawn to familial peace. The buoyant “Over the Hill,” with untreated acoustic guitar, violin, autoharp, and mandolin (courtesy of Richard Thompson), frames Martyn as a road-weary lush finally ready to go home (“Can’t get enough of sweet cocaine/Get enough of Mary Jane/Going back to where I came from/Going rolling back home again”). Here, “over the hill” isn’t a euphemism for old age, it’s the Tolkien-esque visual of a hobbit returning to the Shire, their abode creeping out as they draw closer. And the hymnal “May You Never” brought Martyn the most attention in his career, thanks to a cover by Eric Clapton. In late 1971, Martyn recorded it as a standalone single, but he was unhappy with the instrumentation, which made it sound like a band playing at an island resort. The feel didn’t match the lyrics, which are simple well-wishes to what seems like a friend:

You’re just like a great strong brother of mine
You know that I love you true
And you never talk dirty behind my back
And I know that there’s those that do

By stripping the sound down to Martyn and an acoustic guitar, “May You Never” transforms into a lullaby. Beverley had given birth to a daughter in February 1971, and listening to “May You Never,” you can imagine John singing it to one of his children before bed, with a refrain that feels like paternal consolation: “And may you never lay your head down/Without a hand to hold/May you never make your bed out in the cold.” But the song has a bleak subtext, a different kind of entreaty: Don’t be like me.

The last song on Solid Air is a twofer, “The Easy Blues/Gentle Blues,” the first part a throwaway acoustic blooze caricature that Martyn often played live, and the latter a stop-start fadeout with a full band, where he kindly pleads for his partner to help him maintain his compassion, singing, “I’ve been trying to get to hear you say/That you’re never going to let me lose my gentle blues.” Even though it’s a light finale, Solid Air concludes with an explicit rendering of Martyn’s warring impulses: the demonic entertainer with a smiling facade, and the becalmed and content father and husband.

While Solid Air is his most beloved album, Martyn didn’t care for it, thinking it was too rushed, its patchwork nature betraying a lack of commitment. Later in 1973, Martyn committed hard to his musical vision. That year’s Inside Out liquefied his psychic schism into lava and ocean spray, Martyn’s words warbled to the point of unintelligibility. Inside Out is where he fully cuts the line to his folk barge roots, deserting songwriting grounded in specificity for improvisation crudely cut and reassembled in the studio. A cult audiophile treasure, and Martyn’s personal favorite, it was a huge commercial failure.

For a long time, if Solid Air was a touchstone for future musicians, it was a surreptitious one, a whispered classic among the most dedicated of crate diggers. But in the early ’90s, during a stint in Chicago, Martyn was exposed to hip-hop—and through his second son, Spenser—drum n’ bass, acid house, and jungle, which he incorporated into his own recordings. When he went back to the UK, Martyn signed with Go! Discs, the same label as Portishead. After Go! cofounder Andy Macdonald sold it to Polygram, he established Independiente and brought Martyn with him—this time marketed as “the godfather of trip-hop.” Martyn covered Portishead’s “Glory Box” on 1998’s The Church With One Bell, and by the start of the 2000s, Solid Air was being reassessed as a precursor to the spliff-loaded sensibilities of the recombinant pop of the late ’90s. Beth Orton, whose own work would merge folk music with electronic ornamentation, glowingly referred to Solid Air as “one of the first ambient records I ever heard.” “Solid Air” was even included on a 2000 Q magazine compilation CD called Essential Chill Out.

And in November 1999, Martyn’s past reemerged in another random way. A Volkswagen TV commercial aired widely, with a car full of attractive Gen X-ers wordlessly driving a drop-top Cabriolet through the idyllic nighttime hills of Northern California. It was scored to “Pink Moon,” posthumously bringing Nick Drake into contact with the tasteful and adoring audience that eluded him in his lifetime. Toward the end of his own life, Martyn loathed fielding questions about Drake, and called the hipster worship of his late friend “creepy” and “ghoulish.” Perhaps it was borne from guilt: A month before Drake’s suicide, he and Martyn had a vicious argument that was never sorted out. When John got the call that Drake had died in November 1974, he laughed—a “disturbing” laugh—and casually told Beverley, “He did it.” Then he walked out of the room and disappeared for two days.

Symbolically, Martyn left that room forever. If Solid Air exists at the crossroads of a battle between his quietly paternal and belligerently hedonistic sides, the rest of his life would err toward the latter: alcoholism, drug abuse, emotional abuse, physical abuse, divorce, and poor health. For the remainder of the ’70s, as his vices ballooned and his mental health declined, Martyn’s imagination persisted. His seven-album run on Island, from Bless the Weather to 1980’s Grace and Danger, is phenomenal, each LP as unique an auditory subversion of the singer-songwriter movement as anything by Tim Buckley or Joni Mitchell. But it’s Solid Air that exemplifies Martyn’s artistry, a preoccupation with the in-between, as he told The Telegraph in 2006: “There’s a space between words and music and my voice lives right there.”