In recent years large efforts were invested in the development of a semantic desktop as an innovative mean for dealing with information overflow. Nevertheless, user interface concepts which make a semantic desktop accessible for a larger audience are still scarce and few. In this book the traditional desktop metaphor is enhanced with functionality to enable interaction with semantic information. Files become semantic and are thus called siles. Folders are removed all together and are replaced with tags and categories. Instead filters are used, which can be described best as dynamic queries. Several implementations of user interfaces for this abstraction model are presented. Since the results of a query can be numerous it was necessary to design models for the navigation of result lists. Further an intuitive interface for ontology navigation is presented. The concepts have been implemented and preliminary evaluation results are presented.