Abstract : Free access to scientific resources and the role of libraries In the field of scientific publishing, the movement for open archives has led to changes which the author of the article analyses from four points of view. The first highlights the relationship between libraries and publishing and its destabilisation due to digitization. A more historical approach identifies the contribution of three parallel movements: the development of the web, the saturation of the publishing industry and international scientific politics. An approach per discipline gives an overview of ongoing evolution. Finally an economic approach puts the accent on added value from the various players, its remuneration and the limits of the consideration afforded to available documents.