||The Text Encoding Initiative is an international and interdisciplinary standards project established in 1987 to develop, maintain and promulgate hardware- and software-independent methods for encoding humanities data in electronic form. Initially the TEI was jointly sponsored by three established international professional associations (the Association for Computers and the Humanities, the Association for Computational Linguistics and the Association for Literary and Linguistic Computing), which established a small management committee, and appointed two editors to co-ordinate the enthusiastic participation of more than a hundred scholars worldwide. Its remit was to attempt a complete definition of current practice and to produce recommendations or Guidelines for the creation and usage of electronic texts in key linguistic and literary disciplines. The first research phase of the TEI came to an end in 1994 with the publication of TEI P3, which over the next few years was to become the reference standard for the building of the digital library. At the start of the current century, the TEI re-established itself as a membership consortium, jointly hosted by four institutions, two on either side of the Atlantic, and managed by a Board of Directors and its technical work overseen by an elected Council. There are currently nearly 100 members of the Consortium, among them universities, research libraries, academic and other publishers, both non-profit and commercial, as well as scholarly societies and research projects concerned with the design, production and delivery of structured electronic text. One does not, of course, need to be a member of the Consortium to use the TEI, and indeed there are thousands of users worldwide. In 2002 the first major revision of the Guidelines, known as TEI P4, was published. This was a "maintenance release", seeking only to bring the Guidelines up to date with changes in the technical infrastructure, most notably in the use of the W3C's Extensible Markup Language (XML) as its means of expression, rather than the ISO standard SGML used by earlier editions. Since then, work has been proceeding on a complete revision of the TEI Guidelines, TEI P5, initial releases of which are now available from Source Forge. In this presentation we will sketch some of the changes introduced with this new release, in particular the major new module for the description of manuscripts and other kinds of primary sources, based chiefly on the work of the EU-funded MASTER project (1999-2001) and the TEI Medieval Manuscripts Description Work Group (1998-2000), but with significant input also from complementary work done by other agencies, notably the Repertorium of Old Bulgarian Literature and Letters project (1996- ). We will also show how P5's modular construction facilitates the customisation of the TEI scheme for use in a wide variety of literary and linguistic study, and speculate about its likely implications for future encoding work consequent on the internationalisation effects currently under way. The session is intended as "an orientation and workshop", meaning that there will be both a theoretical and a practical aspect. Previous experience with TEI mark-up would be a decided advantage, but is not required.