Grasping Werner Herzog’s mark on film is no easy feat. With some 50 years of moviemaking under his belt, the 70-year-old German stands as one of cinema’s true legends, as well as one of its most daring and adventurous figures. Among the director’s various exploits, he’s dragged a boat over a mountain, cooked and ate his own shoe, tempted the furies of Klaus Kinski, and, um, directed The Killers. But perhaps one of his wildest endeavours came in 1976’s Heart of Glass.

The idea: collect a group of mostly non-actors, enlist the help of an on-set psychiatrist and hypnotize the cast. The onscreen results are unsettling, to say the least, as the hypnotized actors’ actions are disturbingly off as they shake, twitch, burst out in deranged laughter and stare dead-eyed out of the screen. But it all came in hopes of achieving a stylization that would capture the film’s central theme: collective madness.

Despite all this, the plot of Heart of Glass is a simple one. Set in 18th century Bavaria, the story concerns a village whose head glass-maker has died, taking his secret for the town’s “ruby glass” with him. At a loss on how to re-create the precious glass, the villagers rapidly descend into chaos and, in time, utter lunacy. As you can imagine, the feel of the film is a strange one and more than a little out of this world — something that’s magnified by the stirring score from German musical visionary Florian Fricke’s group Popol Vuh.

Speaking of his longtime musical collaborator, Herzog wrote in the liner notes of SPV’s Heart of Glass (a.k.a. Coeur de verre) reissue: “To me, Klaus Kinski was my dearest enemy, my best fiend so to speak, but Florian Fricke kept the balance, he knew a safe way across the abyss: when it came to creative work, he was my dearest friend.”

And while Kinski did not appear in Heart of Glass, Fricke’s score most definitely provides the needed balance. Popol Vuh’s music enters early: as the film’s Nostradamus-like protagonist Hias (played by Josef Bierbichler, the only actor besides the professional glass-blowers not hypnotized for the film) waxes poetic on the fast-approaching end of the world, an eastern-tinged doom-and-gloom instrumental that makes Godspeed You! Black Emperor feel small, floats to the surface. But while Hias begins to speak of “new lands,” the images of a crushing waterfall morph into a sky opening up, and the song follows suit, switching gears with soaring, beautifully melodic guitar leads reaching ever higher into the heavens.

Like much of Herzog’s work from the ’70s, Heart of Glass contains a proper narrative, but also darts off into meditative nature-film territory, capturing breathtaking landscapes — rivers, forests, caverns and seas — in Germany, as well as Yellowstone National Park and Ireland’s Skellig Islands. And it’s in these moments where Popol Vuh’s score becomes crucial, lifting the film with primitive, Old World sounds filtered through a still very modern-sounding rock ’n’ roll template.

Unfortunately, Popol Vuh’s score is used sparingly in Heart of Glass, with the film itself being surprisingly quiet, and many of Fricke’s compositions live only on the soundtrack album. That said, track for track, the record stands as one of the band’s highest achievements.

Graceful and spiritual, the album is a truly transcendental piece of work, offering blissed-out seances that reach a tender beauty rarely heard in the world of rock. While embracing worldly percussion and a heavy East Indian feel via instruments like the sitar, the record comes with some seriously complex guitar leads courtesy of the band’s Daniel Fichelscher, best represented on standouts like the touching tone-setter “Engel der Gegenwart” and skyscraping “Blätter aus dem Buch der Kühnheit.” It all weaves the sort of high-reaching yet meditative atmosphere that countless post-rock bands would attempt to re-create decades later.

Popol Vuh’s music is about trying to take you somewhere else, whether it’s 18th century Bavaria, an Amazonian jungle or simply beyond the drab confines of your own living room. And while the band would shift focus over three decades, the goal remained the same.

Before his death in 2001, Fricke perhaps explained best: “I always find new styles, different forms of playing that I am incorporating into the music of Popol Vuh. But the essence of my music remains the same. The forms are changing, but the essence remains the same. I want to tell you one more thing about this: the essence of Popol Vuh is a mass for the heart. It is a music for love. That’s all.”