Recorded nearly two years after the avant-pop masterpiece Another Green World and the humble, process-based Discreet Music, and one year before Ambient 1: Music for Airports, 1977's Before and After Science represented the collision of Eno's hyper-productivity with a nagging self-doubt. "I used to be led by the work," he explained to NME at the time. "Something would happen and I'd just follow it. This time it wasn't as easy as that. Things seemed to be going in directions which weren't interesting to me any more…I was working against the technique, to some extent."
Again, Eno designed various behavioral processes — classed as technological, personal, social, "and one to do with compositional mathematics or something like that," he said — to direct his players, who included Robert Fripp, Fred Frith, Phil Manzanera, Brian Turrington, Rhett Davies and other frequent guests; the Krautrock musicians Conny Plank, Dieter Moebius, Hans-Joachim Roedelius and Achim Roedelius contributed to "By This River." Building up a massive backlog of material — he wrote 120 tracks in the course of creating the album, and abandoned it three times before finishing it — he ultimately stitched the material into 10 tracks of understated, experimental pop.
For all that, it doesn't break any significantly new ground; even Eno described it as "less brash than other things I've done." There's a more distinct funk undercurrent than in previous Eno records, particularly in murky songs like "No One Receiving" and "Kurt's Rejoinder"; elsewhere, Eno and his collaborators continue to deconstruct pop across songs like the chiming, cod-R&B of "Backwater," the iridescent barroom rock of "King's Lead Hat" and "Here He Comes," a lilting ditty that sounds, at first, like kitschy Christian music. These are offset by slower, more expansive tracks like "By This River" and "Through Hollow Lands (For Harold Budd)," whose title is self-explanatory. For all the record's jumbled qualities — none of them disagreeable — the final four songs are a gorgeous stretch of liquid melancholia, culminating in the bright-eyed lullaby "Spider and I," with its refrain, "We sleep in the morning/ We dream of the ship that sails away/ A thousand miles away." Eno explained, "They're to do with either drifting away or getting lost or being part of the flow of things. And what they're drifting away from is the condition where everything is clear-cut and knowable and everything is in its place and easy to see. Which is a cause partly for celebration and partly for melancholy. It's both exciting and unnerving."