Nono himself referred to the work as a "cantata" . For its pitch material "Il canto sospeso" employs an all-interval twelve-tone row sometimes called the "wedge" series because of its presentation of all the intervals within the octave in expanding order. It is a symmetrical series, whose retrograde is identical to the prime form transposed by a tritone (; ; ). "Il canto sospeso" is regarded today as a "serial masterpiece", and is admired for the variety of ideas achieved with the compositional technique of serialism , while at the same time the work’s expressive content is considered to be unsurpassed by Nono's subsequent works . Although the premiere under Hermann Scherchen's baton in Cologne on 24 October 1956 was a success, the direct reference to Nazi crimes was bound to be controversial at a time when such things were not generally spoken of in Germany . Herbert Eimert, reviewing the concert (on which it appeared in the company of Anton Webern’s opp. 6 and 10 orchestral pieces and Arnold Schoenberg’s "Friede auf Erden"), declared that "Il canto sospeso" "probably left the most significant impression to date of any concert work of the young generation of composers today. … This one work would be enough to legitimize the enigmatic 'legacy of Webern' once and for all" (, translated in ). The choice of texts, however, provoked protracted dissension over the appropriateness of Nono's compositional means to its political content, particularly in the context of Theodor Adorno's recently published "Das Altern der neuen Musik", which associated integral serialism with totalitarian regimes, and his famous phrase, "to write poetry after Auschwitz is barbaric" . Sides in the debate were largely along national lines, between West Germany and Italy. Heinz-Klaus Metzger attacked Nono as "a serial Pfitzner" who exploited such texts "in order to present them at the next important festival to the applause of a delighted bourgeoisie" , while Massimo Mila defended Nono against Metzger's attack . In at least one case opposition to Nono's composition went beyond words. A terror bombing at the Munich Oktoberfest on 26 September 1980 killed 13 people and injured more than 200 others. It is believed to have been directed at the scheduled performance of "Il canto sospeso", which was cancelled as a result.