As early as their inaugural Sun Giant EP, Fleet Foxes aligned themselves with a class of folk musicians trying to expand the genre. Their songs incorporated folk’s most traditional components—lush harmonies, gently strummed acoustic guitars, bucolic imagery—but emboldened them within music that refused to stay in one place. On Crack-Up, Fleet Foxes’ first album in six years, they’ve crafted their subtlest music yet, but also their most dynamic. On the multi-part opener “I Am All That I Need / Arroyo Seco / Thumbprint Scar,” they shift between movements with an occasionally jarring restlessness: one minute leader Robin Pecknold is whispering from a distance, then, suddenly, he’s bellowing and backed by strings.

While Crack-Up is Fleet Foxes’ most distinctive record—one that no longer finds them aligned with any particular movement in indie rock—it also positions them within a musical lineage dating back half a century. Prog folk seems like the most inclusive term to describe this kind of music, signifying artists who brought the ambition and intensity of progressive rock to the simplicity of traditional folk songs. The subgenre distinguishes itself from psych folk with a focus on composition: abrupt shifts, unexpected chord progressions, and multi-part movements that stretch out with ornate arrangements. With the help of defining British groups like Jethro Tull, the Strawbs, and Gryphon, the genre became known for incorporating medieval themes and instrumentation (see: “Midnight Mushrumps”). But as it evolved, artists incorporated their progressive influences more subtly, following in the footsteps of classic albums like Van Dyke Parks’ Song Cycle and Van Morrison’s Astral Weeks.

While the boundaries of prog folk are perhaps tenuous from like-minded subgenres, this album-length retrospective highlights common ground among a number of seminal artists, ones who’ve scoured the sounds of the past and left all its weirdness and beauty intact.

Prototypes

Van Dyke Parks —“Public Domain” (1967)

Van Dyke Parks’ strange, sweeping string arrangements have accompanied masterpieces ranging from Beach Boys’ Smile to Joanna Newsom’s Ys, but he also has an impressive discography to his name. His 1967 debut Song Cycle is one of the decade’s most influential recordings, but—as a cheeky old ad for it suggests—the LP was destined to be a classic but damned to relative obscurity in real time. The more years pass, the better its inscrutable movements and warped sense of melody sound.

The Byrds — “I See You” (1966)

With their songwriter Gene Clark newly departed for solo pastures, new Byrds leaders David Crosby and Jim McGuinn tried something different with Fifth Dimension, a psychedelic collection including their biggest hit (“Eight Miles High”) and some of their most forward-thinking music. With “I See You,” they created their most aggressive recording to date, propelled by atonal guitar freakouts, tight harmonies, and a jazzy rhythm that stops and starts by its own hallucinogenic logic.

King Crimson — “I Talk To The Wind” (1969)

Depending on when you encountered them, King Crimson were a number of things: new-wave nerds on Discipline, hard rock juggernauts on Red, spaced-out jazz heads on Islands. On their 1969 debut, In the Court of the Crimson King, they struck a balance between grandiosity and simplicity. Songs like “21st Century Schizoid Man” illustrated why rockers like Pete Townshend saw the future of the genre in their dystopian anthems, while delicate moments like “I Talk to the Wind” underscored Crim’s place within the ’60s British folk scene.

“Hits”

Van Morrison - “Astral Weeks” (1968)

There’s still no album quite like Astral Weeks. Maybe it’s the ambition of an artist desperate not to be defined by “Brown Eyed Girl” or the all-star lineup of jazz musicians he assembled, but there’s an inimitable beauty to the music that’s inspired everyone from Springsteen to Pecknold, who’s referred to *Astral Weeks *as the “best-sounding album.” The title track, with its iconic opening line (“If I ventured in the slipstream, between the viaducts of your dreams”), remains one of rock’s most intriguing invitations.

Pentangle — “Light Flight” (1969)

Right from the start, Pentangle saw the darkness inherent to British folk music, exploring its grim fairy tales with psychedelic mysticism. They’d eventually dabble in 20-minute epics (Cruel Sister’s “Jack Orion”) and bluesy jam sessions (the title track of 1971’s Reflection), but their rougher edges are apparent in even their most concise compositions. “Light Flight,” the opening track on their 1969 breakthrough Basket of Light,was one of their most accessible moments, but it’s propelled by a jazzy rhythm and groovy structure that makes it feel as elusive as fog lingering over a lake.

Popol Vuh — “Oh Wie Nah Ist Der Weg Hinab” (1976)

While founding Popol Vuh member Florian Fricke was often more successful achieving a cinematic effect via synthesizers, he was also fascinated by the primitivism of folk and the chug of psych rock. On PV’s astounding Letzte Tage – Letzte Nächte, guitarist Daniel Fichelscher played some of the best solos of his career—somewhere between the skyscraping grooves of David Gilmour and the sitar ragas of Ravi Shankar—and led “Oh Wie Nah Ist Der Weg Hinab” to prog folk classic status.

Joni Mitchell — “Paprika Plains” (1977)

“Paprika Plains,” the centerpiece of Mitchell’s divisive double album Don Juan’s Reckless Daughter and the height of her late ’70s experiments, spanned an entire side of vinyl. Mitchell once said she had performed it so that it would “flow as if it was spoken for the first time.” She succeeds at this by pouring a sea of images and memories into music that swoops and sprawls with relentless energy. All the while, a string arrangement works overtime to imbue her improvised piano playing with a sense of musical logic, creating a somewhat disorienting effect, like hearing someone describe a dream that feels familiar enough to be your own.

Hidden Gems

Michael Chapman — “Rabbit Hills” (1969)

Backed by Bowie sideman Mick Ronson, Michael Chapman’s cult favorite Fully Qualified Survivor is filled with swaggering compositions that illustrate the English songwriter’s timeless appeal. There’s something almost proto-punk to his delivery in “Rabbit Hills,” the way his words trail off distractedly while maintaining an edge of conviction. The secret to this song’s grand scope—how it feels like a towering anthem with its traditional verse-chorus structure—is emblematic in the chord changes that follow each chorus, a jazzy progression that feels unexpected each time it hits. “Is it just my imagination,” Chapman asks repeatedly, hinting at the subconscious thrill this song provides.

Linda Perhacs — “Chimacum Rain” (1970)

Up until 2014, Parallelograms was Canyon folk singer Linda Perhacs’ only studio album. It’s perhaps best known for “Chimacum Rain,” a song defined by her dazzling vocal arrangements (though her guitar-playing is equally alluring). As she sings of falling rain, she layers her voice so that each word lands just as naturally. “I’m spacing out,” she coos as the stakes intensify in the song’s middle section, “I’m seeing silence between leaves.” If you close your eyes, you can see it too.

Roy Harper — “The Same Old Rock” (1971)

Roy Harper’s masterpiece Stormcock consists of four lengthy compositions that shift nauseously between stripped-back beauty and dramatic intensity. “The Same Old Rock” embodies all of the album’s best qualities. Its epic length gives the English singer-songwriter space to stretch out, for the listener to get lost in his hypnotizing cascades of fingerpicking before the music mysteriously fades out, leaving only his voice. The guitars return subtly, his voice now coated in reverb like a halo formed above him.

Judee Sill — “Abracadabra” (1971)

Judee Sill’s “Abracadabra” just might have the oddest structure within the long lineage of two-minute folk songs. Her opening fingerpicking fits with the album’s gorgeous preceding tracks (including one produced by Graham Nash and another that became a minor Turtles hit), but right at the song’s close, Sill adds an almost comically overblown orchestral climax. On her follow-up album Heart Food, Sill would incorporate her symphonic skills more subtly. But here, her arrangement is the aural equivalent of sliding all the paperwork off your desk in one dramatic sweep.

Recent Examples

Sun Kil Moon — “Duk Koo Kim” (2003)

Between Mark Kozelek’s shoegaze-leaning work with Red House Painters and his stark confessions as Sun Kil Moon, his focus is clearly on slow-moving, longform folk tunes. On 2003’s Ghosts of the Great Highway, he wrote the most traditional songs of his career, telling stories about faded figures from history and looking to his own past for answers. On album highlight “Duk Koo Kim,” the music shifts between mournful slowcore, fingerpicked folk, and psychedelic tropicalia, but it retains the austerity of Kozelek’s best work, making its various movements feel heavy and united.

Grizzly Bear — “Lullabye” (2006)

Grizzly Bear came to prominence during the mid ’00s freak folk movement, when musicians like Devendra Banhart and Cocorosie were taking the genre to absurd extremes. While their contemporaries were embracing folk’s more playful tendencies, Grizzly Bear were always a bit fussier, focussed on immaculate song structure and pitch-perfect harmonies. A highlight off their classic sophomore LP Yellow House, “Lullabye” is a stark mood piece that grows increasingly delirious with every chord change and burst of harmony.

Joanna Newsom — “Have One on Me” (2010)

Of all the artists who emerged from freak folk, Joanna Newsom is the one who evolved the fastest, shrugging off the cutesy affectations and idiosyncrasies the subgenre had come to represent. The title track of her 2010 triple album ranks among her most astounding compositions, notable for inorganic transitions that stand out from her characteristically graceful catalog. Around the 9:45 mark, the vocal and string arrangements drop out entirely, leaving only Newsom’s voice and harp to lead you ’round the final bend.

Jessica Pratt - “Game That I Play” (2015)

On paper, Jessica Pratt’s On Your Own Love Again is a fairly simple album: nine songs featuring little more than her acoustic guitar and voice, sharing cryptic stories of lost love. Beneath the surface, Pratt’s songs are rife with complexities. Often, she’s playing with time in ways that makes her music bend and warp (most literally in the subtle pitch-shifts of “Greycedes”). “Game That I Play” is one of the album’s most upbeat melodies—replete with an actual “la-da-da” refrain—but at the end, she tags on a strange coda that subverts the preceding loveliness.

Fleet Foxes - “Third of May / Ōdaigahara” (2017)

Not quite a return to form, this nine-minute slice of soulful Americana draws a line in the sand between Fleet Foxes and the big folk acts that emerged in their absence. From the Lumineers’ massively popular refinement of the genre to just two syllables, to Mumford & Sons’ Grammy-winning soundtrack for car commercials yet to be filmed, the idea of folk musicians reaching for the rafters has grown more prosaic since the 2011 release of Helplessness Blues. As a comeback, “Third of May” is just enough of a reinvention to feel refreshing, while maintaining the catharsis and energy that first made Fleet Foxes stand out from the pack.