<P> At the turn of the century, music was characteristically late Romantic in style . Composers such as Gustav Mahler, Richard Strauss and Jean Sibelius were pushing the bounds of Post-Romantic Symphonic writing . At the same time, the Impressionist movement, spearheaded by Claude Debussy, was being developed in France . Debussy in fact loathed the term Impressionism: "I am trying to do' something different--in a way realities--what the imbeciles call' impressionism' is a term which is as poorly used as possible, particularly by art critics" (Politoske and Martin 1988, 419). Maurice Ravel's music, also often labelled as impressionist, explores music in many styles not always related to it (see the discussion on Neoclassicism, below). </P> <P> Many composers reacted to the Post-Romantic and Impressionist styles and moved in quite different directions . The single most important moment in defining the course of music throughout the century was the widespread break with traditional tonality, effected in diverse ways by different composers in the first decade of the century . From this sprang an unprecedented "linguistic plurality" of styles, techniques, and expression (Morgan 1984, 458). In Vienna, Arnold Schoenberg developed atonality, out of the expressionism that arose in the early part of the 20th century . He later developed the twelve - tone technique which was developed further by his disciples Alban Berg and Anton Webern; later composers (including Pierre Boulez) developed it further still (Ross 2008, 194--96 and 363--64). Stravinsky (in his last works) explored twelve - tone technique, too, as did many other composers; indeed, even Scott Bradley used the technique in his scores for the Tom and Jerry cartoons (Ross 2008, 296). </P> <P> After the First World War, many composers started returning to the past for inspiration and wrote works that draw elements (form, harmony, melody, structure) from it . This type of music thus became labelled neoclassicism . Igor Stravinsky (Pulcinella and Symphony of Psalms), Sergei Prokofiev (Classical Symphony), Ravel (Le tombeau de Couperin) and Paul Hindemith (Symphony: Mathis der Maler) all produced neoclassical works . </P> <P> Italian composers such as Francesco Balilla Pratella and Luigi Russolo developed musical Futurism . This style often tried to recreate everyday sounds and place them in a "Futurist" context . The "Machine Music" of George Antheil (starting with his Second Sonata, "The Airplane") and Alexander Mosolov (most notoriously his Iron Foundry) developed out of this . The process of extending musical vocabulary by exploring all available tones was pushed further by the use of Microtones in works by Charles Ives, Julián Carrillo, Alois Hába, John Foulds, Ivan Wyschnegradsky, Harry Partch and Mildred Couper among many others . Microtones are those intervals that are smaller than a semitone; human voices and unfretted strings can easily produce them by going in between the "normal" notes, but other instruments will have more difficulty--the piano and organ have no way of producing them at all, aside from retuning and / or major reconstruction . </P>

Two dominant jazz trends in the later part of the 20th century were post- modernism and