Anthony Tommasini in the NYT:
Schoenberg’s use of systematized sets of all 12 pitches of the chromatic scale — all the keys on the piano from, say, A to G sharp — was a radical departure from tonality, the familiar musical language of major and minor keys.
Seized with excitement over his breakthrough, Schoenberg predicted that the 12-tone technique would assure the supremacy of Germanic music for another hundred years. He could not have been more wrong. His system spread well beyond Germany, but with far less impact than he had hoped.
Still, the invention of the 12-tone system was arguably the most audacious and influential development in 20th-century music. Its impact can be heard today in works far removed from the knotty scores of composers like Milton Babbitt, Pierre Boulez, Charles Wuorinen and its other formidable practitioners during its heyday in the third quarter of the last century. Elements of 12-tone style turn up even in Broadway shows and film scores. Yet an overwhelming majority of music lovers have no idea what the technique is, what exactly the music sounds like or what the fuss was all about.