...is an XML-based architecture for authoring, producing, and delivering information... DITA divides content into small, self-contained topics that can be reused in different deliverables. The extensibility of DITA permits organizations to define specific information structures and still use standard tools to work with them... DITA specifies three basic topic types: Task, Concept and Reference.
Creating DITA content consists of writing topics and maps. A map contains links to topics, organized in the sequence (which may be hierarchical) in which they are intended to appear in finished documents. A DITA map defines the table of contents for deliverables, and can also specify which topics link to each other. DITA map and topic documents are XML files.
When DITA was released as a public XML standard in 2001, IBM contributed the Dita Open Toolkit, the first DITA-compliant processor. The toolkit transforms DITA content into output formats like PDF, HTML, and Online Help, and can be extended to handle arbitrary specializations and arbitrary output formats. Open Source. http://dita-ot.sourceforge.net/doc/ot-userguide/xhtml/
Darwin Information Typing Architecture (DITA) is built on John Carroll's theories of Minimalism and Robert Horn's theories of Information Mapping. http://en.wikipedia.org/wiki/Minimalism_(technical_communication)