Diverse analytical methods based upon pitch organization in Bartók's music are, with a single exception, products of the second half of the century. To see them and their differences in perspective, it will be well to summarize first what happened generally in the earlier half of the century and after that to outline briefly the particular circumstances facing the Bartók analyst. During the first two decades of the century it was the new sounds of all avant-garde music that provoked the most immediate and sharpest response from critics, but naturally enough, discourse about the music itself was conducted largely along aesthetic rather than technical lines. A shift occurs in the 1920s, the landmark being Schoenberg's development of his twelve-tone method and the debates surrounding it. During the next two or three decades, the literature fairly bristles with technical discussions: pantonality, atonality, bitonality, polytonality and pandiatonicism are some of the terms that date back to this period; even Bartók, a notorious non-participant in these discussions, weighs in with the term polymodality. A second landmark is produced in Paul Hindemith's The Craft of Musical Composition, perhaps the first comprehensive theory of pitch organization of twentieth-century music. This tradition-oriented theory, largely dismissive of Schoenbergian assumptions, was influential for a while, but eventually fell into neglect, exactly in proportion to the ascendancy of Schoenberg's ideas and their ramifications. The latter came to be the principal force in the thinking of most analysts during the second half of the century, especially in America.