This pioneering album of ambient electronic music was recorded in 1975. The music was recorded and played by Edgar Froese (mellotron, guitar, synth, organ, gong), Chris Franke (moog, other synth, gong, organs and piano) and Peter Baumann (pianos, organ, "arp" and voice).
The dreamy music swirls and meanders through crests and troughs over various rhythmic textures, sometimes soaring, at other times bubbling, droning or fluttering. Some sections sound like symphonic passages and the music encompasses many moods, from light-hearted and cheerful to eerie to joyful and uplifting.
I also highly recommend the later solo work of Peter Baumann which is more mainstream and accessible, sometimes even downright catchy. Other enduring German experimental music from the same era includes Monster Movie by Can, Movies by Holger Czukay and Bruder des Schattens by Popol Vuh. If you love this kind of atmospheric instrumental music, you'll definitely also want to explore the work of Autechre.