At the start of the 1950s, European architecture was in crisis. The new neighborhoods and residential areas, designed to functionalist criteria and built hastily after the Second World War, were unable to keep the promises previously made by the architectural avant-garde. If modern architecture was to offer plausible alternatives, it would have to reinvent itself. In doing so, it turned to questions posed by the visual arts at the start of the twentieth century. Architecture, in addition to art, now developed a "primitive," extra-rational perspective which offered the ideas of New Brutalism a platform. By contrast, structuralism was an attempt to express the philosophy of the period through architecture. With the help of 150 illustrations and drawings, the concepts of both these major streams of postwar architecture are introduced. This book establishes a connection between the early concepts of the New Brutalists and the later built projects of the structuralists. It connects an expanded perception of the physical world with the "rational" aims of the architects of this period.