This introductory article shows how to create XML Document Type Definitions (DTDs) and well-formed, well-defined XML files that can be validated by the XML parser of your choice. While you don't have to include a DTD with every XML file you produce, doing so will make your life a lot easier. Not only will a DTD enforce the syntax you've established for your XML files, it will also allow your files to be parsed by a validating XML parser. Code samples include DTD and XML document examples.
The Darwin Information Typing Architecture (DITA) is an XML-based architecture for authoring, producing, and delivering technical information. This article introduces the architecture, which sets forth a set of design principles for creating information-typed modules at a topic level, and for using that content in delivery modes such as online help and product support portals on the Web. This article serves as a roadmap to DITA: what it is and how it applies to technical documentation. The article also links to representative source code.