Cluster was one of the pioneering electronic music groups which popped out of Germany's electrical grid in the late 1960's. While Kraftwerk motored down the Autobahn, and Tangerine Dream used sequencers to explore the subconscious mind, Cluster sought out the secret musical language of factory machinery.

Cluster took form in the late 1960's as Kluster, and consisted of Conrad Schnitzler (known to some as Con), Dieter Moebius, and Hans-Joachim Roedelius. After the recording of three LPs, Schnitzler parted ways with Moebius & Roedelius. Schnitzler retained the rights to the Kluster name and Moebius and Roedlius continued as "Cluster", briefly joined by Conny Plank on their first album. Cluster would prove itself to be very durable and innovative. Before long, their reputation was such that Brian Eno opted to make two recordings with the group. Cluster also merged with Michael Rother (of NEU! and early Kraftwerk fame) to form Harmonia, which Brian Eno dubbed "the world's most important rock group".

Cluster's compositions cover a broad portion of the experimental electronic musical spectrum. The music is sometimes a sonic tint, sometimes a nineteenth century dreamscape superimposed on the present, sometimes sounds like electrons pondering the course of their orbits, and at other times resembles a factory playing its own music, cloaked by the secretiveness of night.