The collection of the present essays in Crossing frontiers draws a picture of the presence of Spanish architectural culture abroad between 1939 and 1975, through the study of international periodical publications, exhibitions and congresses, unravelling the ideas that defined, from abroad, a kind of history of Spanish architecture in those decades. Thus, cultural production and media transmission weave an original web which proposes an “archive” of modern Spanish architecture “seen from abroad”, revealing what had been hidden for years to achieve this. This approach has allowed the reassessment of figures, buildings, images and texts that were dismissed by conventional historiography, illuminating them with a new energy which has led us to highlight a highly expressive “periphery”, capable of interacting with wider contexts, gaining new and surprising meanings. Therefore, we find ourselves on a complex and articulated terrain in which different people and circumstances interrelate and where the usual interpretative stereotypes –“modern movement”, “continuity” or “rupture”– are put in check by the historic-critical reading of events. The texts collected in this anthological volume do not intend to exhaust the study of this period; there are still many untouched subjects which come up in connection with open discussions; more than to a synthesis they respond to a “way” of relating to history. When we close a door many others open.