Atonality

Ending of Schoenberg's "George Lieder" Op. 15/1 presents what would be an "extraordinary" chord in tonal music, without the harmonic-contrapuntal constraints of tonal music.

Atonality in its broadest sense is music that lacks a tonal center, or key.^[1] Atonality, in this sense, usually describes compositions written from about the early 20th-century to the present day, where a hierarchy of harmonies focusing on a single, central triad is not used, and the notes of the chromatic scale function independently of one another.^[2] More narrowly, the term atonality describes music that does not conform to the system of tonal hierarchies that characterized European classical music between the seventeenth and nineteenth centuries.^[3] "The repertory of atonal music is characterized by the occurrence of pitches in novel combinations, as well as by the occurrence of familiar pitch combinations in unfamiliar environments".^[4]

The term is also occasionally used to describe music that is neither tonal nor serial, especially the pre-twelve-tone music of the Second Viennese School, principally Alban Berg, Arnold Schoenberg, and Anton Webern.^[3] However, "as a categorical label, 'atonal' generally means only that the piece is in the Western tradition and is not 'tonal'",^[5] although there are longer periods, e.g., medieval, renaissance, and modern modal music to which this definition does not apply. "Serialism arose partly as a means of organizing more coherently the relations used in the pre-serial 'free atonal' music. ... Thus, many useful and crucial insights about even strictly serial music depend only on such basic atonal theory".^[6]

Late 19th- and early 20th-century composers such as Alexander Scriabin,^[7][8] Claude Debussy,^[9] Paul Hindemith,^[10][11] Béla Bartók,^[12] Sergei Prokofiev,^[13][14] Igor Stravinsky,^[15][16] and Edgard Varèse,^[17] have written music that has been described, in full or in part, as atonal.^{[excessive citations]}