The marketing falls short of the first question : what do we want to do ? The vocation of the libraries and document centres comes within the professional tradition of document and universal service. The strategy requires defining one's position towards the administrative supervision, partners or competitors, and users. After having chosen an audience, it is necessary to precise the service which comes up its expectations. The marketing-mix makes easy the strategie choices if it is suited to our specific activities. Its rewieved variables will become : the services offer, the « servuction » and the contract with users and communication. It's possible to fit the marketing on libraries and documentation centres without betraying their specificities. It remains to collate it with their area.