This document provides an introduction to digital textual editing using the Text Encoding Initiative (TEI). It discusses how TEI, an XML standard, can be used to encode metadata, structure, and other semantic information about digital texts. This extra semantic layer allows TEI encoded texts to be transformed and presented in various formats like HTML, plain text, or databases. The document provides examples of how elements in a TEI encoded XML file can represent different text structures, and how XSLT transforms can convert the XML to HTML or other output formats for viewing texts in different contexts.