This paper describes work that was done at Athabasca University as part of the "EduSource Canada" project. This work centered around learning object development based on pre-authored educational content. The major outcomes of the work were the development of an explicit semantic structure with strong educational focus for learning objects, and the implementation of that structure, using platform/software-independent XML technology. An explicit semantic structure for educational content has some significant advantages: it enables faster publishing of material in different formats using automated processes; it allows institutions to participate in seamless content exchange with other institutions; and it enables more accurate discovery and reuse of learning objects within learning object repositories.