The Text Encoding Initiative.
The Text Encoding Initiative (TEI) is a consortium which collectively develops and maintains a standard for the representation of texts in digital form. Its chief deliverable is a set of Guidelines which specify encoding methods for machine-readable texts, chiefly in the humanities, social sciences and linguistics. Since 1994, the TEI Guidelines have been widely used by libraries, museums, publishers, and individual scholars to present texts for online research, teaching, and preservation. In addition to the Guidelines themselves, the Consortium provides a variety of supporting resources, including resources for learning TEI, information on projects using the TEI, TEI-related publications, and software developed for or adapted to the TEI.
One of the common book models used to describe a document. It competes with other book models such as DTD (ISO 12083), DocBook, NLM (another DTD), DTBook, and even ePUB. A completely different approach is DITA (Darwin Information Typing Architecture)
- Rich, expansive, accommodating
- Collaborative creation: TEI Consortium
- Created for scholarship, not publication
- Own table model (can invoke CALS or XHTML)
- Can invoke TeX or MathML for math
- Enormous resource; TEI Lite is too simplistic
 TEI Lite
TEI Lite is a specific customization of the TEI tagset, designed to meet "90% of the needs of 90% of the TEI user community". Due to its simplicity and the fact that it can be learned with relative ease, TEI Lite has been widely adopted, particularly by beginners and by big institutional projects that rely on large teams of encoders to markup their documents.