serialism. Anton Webern became the leading figure. Olivier Messiaen, who uses in his works among others musical techniques of non-European musical cultures, but also methods of serial music, is the teacher of some of the composers who cause the most sensation there. Among them are: Pierre Boulez (also working as a conductor of "Neue Musik") Karlheinz Stockhausen (among others composer of electronic music and active at the Studio for Electronic Music (WDR) in Cologne) Luciano Berio Mauricio Kagel (experimental music theatre) Iannis Xenakis (Important in this context are also the Institute for New Music and Music Education (INMM) Darmstadt with its annual spring conference and the Darmstadt International Music Institute (IMD), which has an extensive archive of rare recordings, especially of earlier events of the International Summer Courses for New Music. The recordings are available on various media; since at least 1986 also on digital media). While in the pre-war period the main impulses for the development of New Music came from Central Europe, primarily from the German-speaking countries, and other avant-gardists, for example Charles Ives in the US, received little attention, the development now became increasingly international. Traditionally strong musical countries such as France (with Olivier Messiaen, Pierre Boulez and Iannis Xenakis), Italy (Luciano Berio, Luigi Nono) made important contributions, others such as Poland (Witold Lutosławski, Krzysztof Penderecki) or Switzerland with Heinz Holliger and Jacques Wildberger joined in. In the US, the circle around John Cage and Morton Feldman was significant for Europe. It was not atypical for post-war developments in Germany that the emigrated musicians could contribute little, but rather that the "new generation" (especially Karlheinz Stockhausen) became influential – with considerable support for example from France: as a teacher of Stockhausen and Boulez, Messiaen was a regular guest at the International Summer Courses in Darmstadt. In this sense, music may even have helped in the post-war peace process. Last but not least, some important representatives of New Music found their way from elsewhere to their places of work in Germany, such as György Ligeti from Hungary, Isang Yun from Korea and Mauricio Kagel from Argentina. The most important (albeit controversial) theoretician of New Music in the German-speaking world is Theodor W. Adorno (1903–1969), a student of Alban Berg. In his Philosophy of New Music, published in 1949, Adorno argues in favour of Schoenberg's atonal compositional style and contrasts it with Stravinsky's neoclassical style, which was seen as