Hans-Joachim Roedelius (born 1934 in Berlin) is a German composer and keyboard player from the first wave of West German electronic music. With Dieter Moebius he formed Cluster, and with Moebius and Michael Rother the trio Harmonia, two groups that made quiet, repetitive electronic records and later worked with Brian Eno. Since the late 1970s he has also built a large solo catalogue of short, melodic piano and keyboard pieces. Roedelius met Moebius and Conrad Schnitzler at the Zodiak Free Arts Lab in Berlin, and the three formed Kluster.