The Collection Art and Architecture AA MUSAC propounds a transversal reading of the works of artists and architects who advance a critical vision of the contemporary world through their production. In this order of ideas, Yona Friedman’s monograph analyses, in various texts, the fundamental aspects of his work as well as the context from which it emerges. Frampton visits Friedman’s theoretical contributions and the close working relationship they had in the 1960’s; Orazi on his part makes a profound analysis of Friedman’s reflections on Mobile Architecture, the Spatial City and the user’s role in its construction. Hans Ulrich Obrist contributes with two interviews featuring Yona Friedman’s impressions of his latest projects, his idea of the expanded museum and the future of his archives. The unpublished texts Friedman wished to share with us for this publication address his concerns about the role of the contemporary museum and the projects he himself has undertaken in this regard. He also analyses Europe viewed as great metropolis with its possibilities for mobility, interaction and social development.