Based on Schoenberg's
12-tone system which was continued by his student Anton von Webern
. Mostly evident in the music of the 1950s and 60s but appreciation was limited to university professors and their students. Serialism used a strict musical formula that was difficult to play. Composers who used this technique were Milton Babbitt and Pierre Boulez, to name a few.
"Structures" by Pierre Boulez.