Information units -- in MediBook the notion MediaBrick is used -- are associated with concepts, whereby each MediaBrick is described by metadata. Furthermore MediaBricks are associated with each other by rhetorical- didactic relations in such a way as to put them into a context -- e.g. MediaBrick A 'deepens' MediaBrick B -- thus building the MediaBrickSpace. Since in MediBook we are dealing with educational content we use the Learning Objects Metadata (LOM) [1] for the description of the information units. Using this widespread IEEE proposal for a standardized description of "learning objects" other systems are able to access MediBook resources. MediBook is designed to deal with resources of different formats such as plain text, images, graphics, video, audio or animations which may contain information, theses, motivations, exercises, etc. Existing resources shall be integrated in order to support reuse of multimedia-elements which creation often is very expensive.