The Text Encoding Initiative Guidelines for Electronic Text Encoding and Interchange (TEI), first published in 1994, quickly became the standard for encoding literary texts. The TEI was widely adopted by libraries for its promise of discoverability, interoperability, and preservation of electronic texts, but the TEI's monolithic nature inspired the codification of library-specific practice. Since 1999, libraries have relied on the Best Practices for TEI in Libraries (http://purl.oclc.org/NET/teiinlibraries) to guide their work with encoded texts. In April 2008, the TEI in Libraries special interest group (SIG) and the DLF-sponsored TEI Task Force partnered to update the Best Practices. The revision was prompted by the release of P5, the newest version of the TEI, and the desire to create a true library-centric customization. The revised Best Practices contain updated versions of the widely adopted encoding 'levels' - from fully automated conversion to content analysis and scholarly encoding. They also contain a substantially revised section on the TEI Header, designed to support interoperability between text collections and the use of complementary metadata schemas such as MARC and MODS. The new Best Practices also reflect an organizational shift. Originally authored by the DLF-sponsored TEI Task Force, the current revision work is a partnership between members of the Task Force and the TEI Libraries SIG, with the SIG taking the lead. As a result of this partnership, responsibility for the Best Practices will migrate to the SIG, allowing closer work with the TEI Consortium as a whole, and a stronger basis for advocating for the needs of libraries in future TEI releases. If you work with encoded texts or simply want to learn more, please join me for the Best Practices for TEI in Libraries brown bag session. I will discuss the: motivations governing encoding in the context of libraries; historical context for the development of the Best Practices; and TEI Header and encoding levels recommendations.