The purpose of this study is the investigation of pitch-class multiplication and the application of the technique in the music of Pierre Boulez based on his composition Le mcniaui sans maître (1952-55). My study proceeds in two parts. The first part provides an examination of pitch-class multiplication. The pitch organization of this work are derived from a twelve-tone row by the transposition of its segmental subsets, which Boulez calls multiplication. In the first part, I examine the process of multiplication and how it works in Le marteau. In the second part attention is paid mainly to the analysis of pitch structure and formal portions, focusing on the third and seventh movement. In the analysis of the movements I examine the features of pitch organization derived from multiplication, and how Boulez uses it in order to control and organize not only structure of pitch-class but also overall structure of the work.