The optimal version of a document can depend on the user's need and the presentation device, and can govern choices of content as well as style. The content needed for multiple versions of a document can be included in a single document structure and identified by means of tags or by a content selection node. Tags allow the user to specify a desired version, while selection nodes allow the content to be automatically selected, styled and formatted to optimize a set of constraints. Content alternatives may be generated automatically from original content.