Karlheinz Stockhausen (22 August 1928 – 5 December 2007) was a German composer, widely acknowledged by critics as one of the most important but also controversial composers of the twentieth and early twenty-first centuries. Some of his notable compositions include the series of nineteen Klavierstücke (Piano Pieces), Kontra-Punkte for ten instruments, the electronic/musique-concrète Gesang der Jünglinge, Gruppen for three orchestras, the percussion solo Zyklus, Kontakte, the cantata Momente, the live-electronic Mikrophonie I, Hymnen, Stimmung for six vocalists, Aus den sieben Tagen, Mantra for two pianos and electronics, Tierkreis, Inori for soloists and orchestra, and the gigantic opera cycle Licht.