Of all of the acoustic instrumental groups, none has had a greater impact on the development of concert music in the twentieth and twenty first centuries than percussion. Of this group, the subset that has been developed most extensively is the group known as bar or mallet percussion. These instruments have not only been dramatically altered and modernized from their original, pre-twentieth-century ancestors, but the techniques used to play these instruments have been developed and improved upon as well. These new developments with the instruments and the techniques used to play them have enabled many composers to write music with sounds and timbres that did not exist in written music prior to the twentieth century. The main focus of this study is the exploration of newly developed notational devices, instruments and techniques and the impact that these developments have had on concert music written during the twentieth century. Chapter 1 explores new developments in Western bar percussion instruments. Chapte
