<p> This treatise focuses on the evolution of the xylophone in the music of Dmitri Shostakovich. The xylophone occupied an important position in Shostakovich's aesthetic, evidenced in the exposed solos of the first <i>Jazz Suite </i> and the <i>Polka from The Golden Age.</i> In his symphonies, Shostakovich's use of the xylophone expands the role of the instrument from a demarcation or coloristic device to a vehicle of complex cultural and personal ideas ranging from the struggle of the Soviet people under Joseph Stalin, the composer's own hatred of war, and prominently, the multi-faceted idea of betrayal. This document presents a biographical overview of Shostakovich's life, an overview of the history of the xylophone from antiquity through the Twentieth Century, and an analysis of the use of the xylophone in Shostakovich's symphonies. Rhythmic and melodic motives, orchestrational effects, and pitch class relationships are examined in addition to specific score examples.</p>