Debussy's return to abstraction and classical form precedes Schoenberg's by five years. Between 1909 and 1920 Schoenberg composed only one piece of absolute music, the Six Little Pieces op. 19, and their extreme brevity is an index of the formal problems of composing atonally without the support of a text. In 1920 he began work on the much more extended Five Piano Pieces op. 23. The last of these pieces is the first twelve-tone or serial composition. As every schoolboy knows this is a method of composition whereby the basic material of a piece is derived from 'a particular ordering of the twelve pitch classes', normally called a row or series. (Professor Winn's account can be recommended.) Schoenberg invented this technique in order to reclaim the 'lost' territory of abstract instrumental music. Much has been made of the revolutionary nature of serialism, but it was as much an attempt to recover the past as Stravinsky's 'neo-classicism'. The fifth piano piece op. 23 is a highly idiomatic, Viennese waltz, while the first piece is a homage to the Brahms of the late intermezzi. The typical serial procedures - canons in retrograde inversion and the like - look even further back to the early polyphonists whom both Schoenberg and Webern admired. The result in word-setting was a correspondence between poetry and music along 'the axis of construction' rather than 'the axis of emotion'. This emerges very clearly in the fourth movement of the Serenade op. 24, a setting of a Petrarch ...