A wide array of possible solutions to encoding matters is demonstrated in the TEI Guidelines which therefore should be considered a reference manual rather than a tutorial. Mastering the complete TEI encoding scheme implies a steep learning curve, but few projects require a complete knowledge of the TEI. Therefore, a manageable subset of the full TEI encoding scheme was published as TEI Lite, describing 131 elements. Originally intended as an introduction and a stepping stone to the full recommendations, TEI Lite has, since publication in 1995, become the most popular TEI DTD (Document Type Definition) and proves to meet the needs of 90% of the TEI community, 90% of the time (with about 20% of the elements) (Burnard and Sperberg-McQueen 1995).
Probably the most widely used and frequently referenced TEI customization is tei_lite, a subset of some fifty elements claiming to satisfy the needs of 90% of TEI users, as evidenced by their actual practice in creating digital texts. This was originally produced for a TEI training workshop back in 1997, but with some updating has continued to be useful in a very wide range of contexts, to the extent that some people think that it is the TEI schema.TEI Lite is included (as an Exemplar) with the standard release of TEI, in source and derived forms.