The colloquium held at the Archive of the World of Work, one of the five archive centres dependent on the National Archives, from 2 to 4 December 2004, was born of the wish of the regional section Nord-Pas-de-Calais-Picardie to celebrate, locally, the centenary of the French Archivists’ Association. Organised with the cooperation of the Centre for Historical Research on Northwest Europe (University of Lille 3), this colloquium based its scientific project on a multidisciplinary approach involving archivists and academics, professionals and users, with natural close links and complementary purposes. The call for communications, issued in 2002, focused on a broad chronological period, from antiquity to the present day, and an open geographical area, comprising the north-western regions of France (Nord, Pas-de-Calais, Picardie, Normandy), Belgium, the Netherlands, the north of Germany, Denmark, Finland, Sweden, Norway, Iceland, the United Kingdom and Ireland. In this space with no apparent historical coherence, political ties with variable geometry and polymorphic economic relations, of which the European Union is the last representation. In this context too, by virtue of their wealth or indigence, archives are the prime witness of the relationship between space and time, the flow and reflux of activities and authority, as well as the unwavering relationship between governance and memory, the nature and movement of which require chronological and seminal tags. The interventions were intended to provide researchers, genealogist historians and amateurs with keys to access this memory, in order to shed light on the production context and the content of the material produced, transmitted, leguminated and exploited. They have been divided into three themes, understanding in their historical dimension the memory object — the archives — resulting from the primary action of the structures and individuals that generate it; the officer — archivists — who ensures that the memory is sustainable; action — archiving — which is necessary for preservation and based on science, the principles of which have gradually been forged.