Text Encoding Initiative wrote:The TEI Guidelines for Electronic Text Encoding and Interchange define and document a markup language for representing the structural, renditional, and conceptual features of texts. They focus (though not exclusively) on the encoding of documents in the humanities and social sciences, and in particular on the representation of primary source materials for research and analysis. These guidelines are expressed as a modular, extensible XML schema, accompanied by detailed documentation, and are published under an open-source license. The Guidelines are maintained and developed by the TEI Consortium, through its Council and editors, with the support and participation of the TEI community.

Text Encoding Initiative wrote:The TEI encoding scheme is of particular usefulness in facilitating the loss-free interchange of data amongst individuals and research groups using different programs, computer systems, or application software. Since they contain an inventory of the features most often deployed for computer-based text processing, the Guidelines are also useful as a starting point for those designing new systems and creating new materials, even where interchange of information is not a primary objective.