What is Document Template Definition (DTD)

E-learning promotes the use of structured learning materials which extend the book based metaphor of chapters, lists and diagrams using markup languages based on HyperText Markup Language (HTML). Educators working with eXtended Markup Language (XML) have a variety of XML based technologies to choose from: Moodle, Resource Definition Framework (RDF) and Web Ontology Language (OWL). Another option is to use XML to generate web resources from a relational database, such as MySQL, or with a knowledge database, such as Prolog. This chapter looks at how these three technologies can interchange information with the help of new intelligent resources such as the OpenMind project that are beginning to model the world around us. Advances in these areas pave the way for more automatic acquisition of knowledge from existing texts using tools such as MontyLingua to provide a basic semantic understanding of the material and promote interoperability. Examples of the technologies are used to illustrate the benefits of structuring new learning materials, and options for integrating heritage materials are examined.