The book on the Basque cities by José Ignacio Linazasoro was conceived in a cultural climate with a strong presence of the Italian morpho-typological discourse; However, in it the author did not limit himself to applying a general theory to a particular case. In addition to deepening the knowledge of the urban and territorial evolution of a group of towns of medieval foundation on which the system of cities of the Basque Country is largely based, Linazasoro laid with him the bases of certain aspects that he would develop in his career later as an architect; especially, the work with the preexistences, the attention to the way in which the old is related to the new, and the interest in material questions. This paper focuses, on the one hand, on the cultural and professional context in which the book arose and, on the other, on its significance for the later constructed work of Linazasoro.