It could be argued that there's not much to this record; the first piece comprises a pair of tape loops drifting in and out of phase, but actually contains as much silence as tones (technically, it's done on a single piece of tape, but it's in stereo after all, and sounds like a pair of instruments responding to each other). The second suite is a piece by Pachabel played by a string quartet, with each part played to a different timing, causing the instruments to drift in and out of phase with each other.
So, in actual fact, Brian Eno isn't really even on the recording, so why am I rating "his" work so highly? Simply put, the result of his grand design is a pair of pieces of extreme beauty. The sparse and minimalist sounds have both a fascination - in as much as I am always wanting to hear what comes next - and a quality of inducing extreme relaxation. Frankly, if I put this on at night, I'm likely to drift off to sleep before the first piece finishes; it's so minimal that I rarely get to hear it!
So what's the point of buying a record that you're not necessarily going to listen to? Well, besides the beauty of the sounds, it's not often that a non-chemical can create such profound feeling of relaxation - it's like yoga for the mind. Subsequently imitated, but never in my opinion bettered, this is so good that it makes it onto my Desert Island list.