5 th International Conference on Information Communication Technologies in Education ICICTE 2004, Samos, Greece Learning objects, instructional architectures and digital libraries: new perspectives on interoperability. Miguel Ángel Marzal 1 Javier Calzada Prado María Jesús Colmenero Ruiz Aurora Cuevas Cerveró Library & Information Science Department Carlos III University of Madrid Abstract This paper presents the theoretical basis and practical implications of the incorporation of learning objects to Higher Education learning architectures. Assuming that in order to improve their cost-effectiveness such architectures should benefit from the richness of resources that instructional digital libraries have available, the problem is found in interoperability, and proper content description is proposed as a solution from the Library & Information Science (LIS) area. A model for the implementation of a learning object repository in an online doctoral course as part of an ongoing project in the Carlos III University of Madrid, Spain, is finally proposed as main contribution. Introduction In a time when rapid knowledge updating is becoming an increasingly vital competency for students and professionals to achieve in order to properly enter the Knowledge Society, learning environments should be adapted to these requirements. One of the main challenges these environments are facing has been issued by the Information & Communication Technologies, specifically the Internet, which has changed the nature of educational resources (Marzal et al., 2003). The traditional, static concept of didactic materials has given way to a new and highly interactive conceptualization of these resources. Recent research (Marzal et al., 2003) has pointed to Learning Objects (LO) as an ideal model of document for education in the Knowledge Society, not only for their interactive nature, but also for their reusability, which seems to be the key to make flexible and cost-effective online learning environments feasible. The goal of this paper is to provide a theoretical framework and a prospective model for the incorporation of learning objects to the educational context of Higher Education, and specifically to one of our doctoral courses in the Carlos III University of Madrid. We consider that such learning objects might be included -by means of a proper content description- in learning architectures that allow them to additionally benefit from the richness of the open source learning resources available on instructional digital libraries. 1 Miguel Ángel Marzal: mmarzal@bib.uc3m.es ; Javier Calzada Prado: fcalzada@bib.uc3m.es ; Mª Jesús Colmenero Ruiz: mcolmene@bib.uc3m.es ; Aurora Cuevas Cerveró: accerver@bib.uc3m.es .