As a semantic language, DocBook enables its users to create document content in a presentation-neutral form that captures the logical structure of the content; that content can then be published in a variety of formats, including HTML, XHTML, EPUB, PDF, man pages, Web help and HTML Help, without requiring users to make any changes to the source. In other words, when a document is written in DocBook format it becomes easily portable into other formats, rather than needing to be rewritten.