The article gives a general introduction to the form and function of the TEI header, points out some of the reasoning of the Text Documentation Committee that went into its design, and discusses some of its limitations. The TEI header's major strength is that it gives encoders the ability to document the electronic text itself, its source, its encoding principles, revisions, and characteristics of the text in an interchange format. Its bibliographical descriptions can be loaded into standard remote bibliographic databases, which should make electronic texts as easy to find for researchers as texts in other media, including print. Its major weakness is that it does not yet provide the ability for retrieval across texts in a networked environment, which users may want now or in the future.