This report of a 10-month study performed at the Institut Danois des Echanges Internationaux de Publications Scientifiques et Litteraires (IDE) on its exchange program for duplicate monographs provides an analysis of the working methods and time spent on the various phases, i.e., acquisition, processing, and distribution. The major function of the Institute is to coordinate and centralize Danish exchanges, and IDE is in charge of the exchange of official publications for all Danish libraries, doctoral theses and other publications issued by the University of Copenhagen, and the periodicals of the Danish National Library and the State and University Library of Arhus, as well as serving as the national center for the exchange of duplicate books. (CMV)