This dissertation presents the newly invented system RelAndXML for the management and storage of hypertext-centric XML documents and the according XSL stylesheets. Our sample application area is the course material at university. RelAndXML saves the XML formatted assignments as text modules and remaining parts in a special database. Storing XML documents in databases has been a major topic in database research in the last few years. Approaches on this topic concentrate on data-centric or on document-centric documents. In this thesis, we present a hypertext-centric approach that combines aspects of data-centric as well as document-centric approaches. It enables the reuse of text modules and preserves document order where necessary. Another important feature of RelAndXML is that it supports not only XML elements, but also attributes, comments, and processing instructions. Algorithms for the fragmentation and reconstruction of documents are provided. RelAndXML is a Java-implemented system using an object-re\-lational database. It provides a graphical user interface which allows to create and update the XML and XSL parts of hypertext documents, to insert new or saved text modules, and to generate HTML or XHTML output documents.