This article examines the transfer between precompositional material and score in Pierre Boulez’s Domaines. It demonstrates how this stage of the compositional process and the gestural content of the work derive from and are linked to Boulez’s innovative serial and derivational techniques, because they stem from a desire to emphasize and systematically realize the very harmonic elements and relationships that motivated their development. The article outlines a typology of methods of composing out that are central to Boulez’s compositional style in a broader sense. In this way, beyond elucidating aspects of structural organization that have been overlooked in his music, the article suggests ways of formally defining aspects of his style. What this study adds to our understanding of Boulez’s music from this period is a theoretical framework that explains the functional role of units stressed through sonic and contextual criteria, thus providing insight into the syntactic elements of the musical language and indicating listening and analytic strategies for this music.