It seems that in the world of popular music, the golden period allotted to many great artists spans just one decade. There may be flashes of brilliance afterwards—and even a sizable helping of enjoyable music—but for the most part, once those ten years are up, the genius spigot gets turned off. David Bowie, Pink Floyd, Neil Young, Bruce Springsteen, and Led Zeppelin are just a handful of artists that produced a string of remarkable works year after year, until suddenly running out of gas, anomalies like Young’s Freedom notwithstanding.

Brian Eno, since he stands outside the pop realm in so many other ways, would seem to be exempt from mundane laws like these. But 1982’s Ambient 4: On Land may very well be one of the bookends of Eno’s classic period, with Roxy Music’s 1972 debut the other. He was far from washed up after On Land, as a document as pleasurable as the following year’s Apollo: Atmospheres and Soundtracks would prove. But from there on out, Eno sounded set in his ways, comfortable exploring the nuances of familiar ground rather than lighting out for the territories as he had done so expertly until then. It doesn’t help matters that Eno’s discography at this point begins to dissolve into collaborations and side projects and diversions, until the concept of a true Brian Eno record gets hopelessly muddled. Eno almost certainly likes it that way, and chuckles when uptight squares like myself waste time longing for past glories and getting hung up on questions of authorship.

Eno had tinkered with the idea of ambient music on 1975’s Another Green World, but it still sounded like a revelation when, in 1976, he released Discreet Music. It would give ambient and new age the tone they have been content to maintain to this day, one unlikely ever to change. But if the simple, calm synth pattern was Eno’s most frequently-employed gift to the genres he fathered, it was not his only one. On Land departs from the static and the placid about as often as ambient can before ceasing to be ambient, which is what makes it the last indisputably pioneering Eno album. As Eno has mapped it out here, the terrain at the borders of ambient may grab far more attention than that of Discreet Music. There are sounds and textures striking enough on their own to overcome Eno’s decision not to assemble them into any overt structure.

It was his aim to mimic his experience of recording sounds from a patio in Ghana, transforming it into art by placing a frame around some of it. He wanted to communicate a sense of place in eight tracks, some named for places he had been, some for places he hadn’t, and some for general spaces or ideas like “A Clearing” and “Shadow”. On Land is not so much the soundtrack to a nonexistent movie as it is the soundtrack to the banal experience of standing in a certain place and listening.

That banality, however, reveals something to the open mind. On Land, as ostensibly disorganized as it is, still tugs at emotions, and the effect of the record is not to induce boredom but to disconcert. With Slipknot not competing for that goal, its methods may be too subtle, but there’s an undeniable creepiness present. Ambient music washes over a room rather than dominating it, but On Land makes a space less inviting and less comfortable. One wonders what it was that Eno found so intriguing about the places depicted on this album, but if his representations were accurate, he makes us rather glad that we’re not there. Peeking in on those places from the safety of our own stereos, however, remains a unique trip in the ambient canon, one whose position in Eno’s glorious body of work remains formidable.