At the beginning of the 20th century, composers of classical music were experimenting with an increasingly dissonant pitch language, which sometimes yielded atonal pieces. Following World War I, as a backlash against what they saw as the increasingly exaggerated gestures and formlessness of late Romanticism, certain composers adopted a neoclassic style, which sought to recapture the balanced forms and clearly perceptible thematic processes of earlier styles; see also New Objectivity and Social Realism).
After World War II, modernist composers sought to achieve greater levels of control in their composition process (e.g., through the use of the twelve tone technique and later total serialism). Many of the key figures of the high modern movement are alive, or only recently deceased, and there is also still an extremely active core of composers (e.g., Elliott Carter), performers, and listeners who continue to advance the ideas and forms of Modernism.
Serialism is one of the most important post-war movements among the high modernist schools. Serialism, more specifically named "integral" or "compound" serialism, was led by composers such as Pierre Boulez,Bruno Maderna, Luigi Nono, and Karlheinz Stockhausen in Europe, and by Milton Babbitt, Donald Martino, and Charles Wuorinen in the United States. Some of their compositions use an ordered set or several such sets, which may be the basis for the whole composition, while others use "unordered" sets for the same purpose. The term is also often used for dodecaphony, or twelve-tone technique, which is alternatively regarded as the model for integral serialism.