MPB is a musical practice appeared in the beginning of the 1960s whose polysemy is far from being exhausted by studies of culture. The approach adopted in this dissertation seeks to study it comprehensively as a text - musical sounds, in complex relationships with its lyrics, performances, extramusical discourses and the broader context. I argument that such sounds, organized in musical genres, are discourses - processes of social production of meanings. As such, they are not only mediated by verbal discourses, but also mediate them. Through the construction of a theoretical model that builds on Julia Kristeva s concept of intertextuality I try to stress each text s specificity as it impacts the physical and social body, thus recovering MPB s complexity. A musical genre is seen as a code which connects musical details to the broader social- historic context, constructing identities that also can be deconstructed by the continuous migration between different positions produced by the plurality of musical discourses traversing MPB. By studying musical genres as produced by the collective anonymous, this view emphasizes MPB´s radical alterity. This practice is thus seen as expanding itself beyond a metropolitan university middle class to embrace the social continuum in all Brazil. Musical movements and leaders are situated as discourses of ample social groups which use them to make themselves represented in the contradictory space of mass mediated music. Alternative versions and narratives are presented to account for bossa nova, Jovem Guarda, Tropicália and their relationships to MPB, aiming at the deconstruction of dychotomies and hierarchies. Nationalist and leftist ideology (the national-popular) is seen as only one among the many conflicting discourses that met in the heterogeneous space demarked by MPB, which also discussed in its texts the situation of blacks, women and of dominant cultural centers, sectors, and traditions. The conclusions obtained in this dissertation indicate MPB as a multiform and contradictory field of forces, employing, for the first time in the history of Brazilian popular music, a kaleidoscopic plurality of musical genres (discourses). Prioritizing conflict, debate and contradiction, MPB destructured reified identitary constructions and made multiple subjectivations and positionings possible, producing an influent and lasting political and cultural advancement in the body of Brazilian society.