The concept of New Brutalism has been the victim of a series of misunderstandings, myths and aporias. The initial intentions, devoid of any principle or dogma, have passed from hand to hand. The original definition–if only one can be identified–has been manipulated, diluted and finally fragmented, revealing the necessity of a thorough reconstruction of its trajectory, by sifting through architectural works, theoretical instances, debates and comments scattered, for the most part, in the pages of major international journals over a span of more than thirty years. The aim of this thesis has been to reconstruct the origins and development of the definition of New Brutalism and to reflect on its evolution, with the intention to understand the reasons and methods that have led it to take on an extraordinary dimension, becoming for a moment at least, an important topic in the architectural debate. The extension of the definition of New Brutalism was, if not entirely international, of a considerable vastness, ranging from Europe to the United States, from Japan to South America. Yet New Brutalism cannot be considered a synthesis but rather an attempt to pose profound questions about the course of architecture and the fate of the Modern Movement. Grasping the meaning of this concept in its various declinations and attempts at definition through the historical method required retracing its movement, through the scrutiny of major international journals and essays and the consultation of archival documents. The advent in the debates of the definition of New Brutalism reveals the appearance of an aspiration for an architecture that became an expression of the criticism of the young generations of the 1950s against sentimentalist and vernacular degeneration, at a time of profound crisis in the concept of the Modern Movement. The 1950s, which began with the turmoil of the Unité construction site in Marseille, witnessed the abolishment of cladding and the affirmation of a bare, essential, “basic” architecture. The debates on New Brutalism were not limited to the dimension of a single building, but addressed a new way of understanding the urban dimension, the role of the architect, and an ambivalent collaboration between critics and architects. At the heart of this renewal was the debate on Brutalism, fomented by the works of architects but above all by the aspirations of critics. This research examines the trajectories of the idea of New Brutalism, its origins and etymological roots, with a focus on the theoretical implications at stake through a reading of how it has been conceptualized €“and exploited €“by various protagonists and critics since the early 1950s. The central core of the dissertation has been to chronicle shifts in critical perception, following the contributions Brutalism made to national debates. By questioning and challenging the current categorization of post-war architecture, this research gets to the core of the post-war critical debate, unfolding, through its many actors, its philological incongruities as well as its heroic visions.