The World Wide Web Consortium
We already know that the W3C is the body responsible for defining exactly what XML is, but who is the W3C? The W3C is not a government body; instead, it's a group made up of member organizations (currently more than 400) that have an interest in the World Wide Web. The W3C is hosted by the Massachusetts Institute of Technology, Laboratory for Computer Science (MIT/LCS), in the United States; the Institut National de Recherche en Informatique et en Automatique (INRIA), in Europe; and the Keio University Shonan Fujisawa Campus, in Japan. Currently, it has about 50 full-time staff members.
How does W3C set up specifications for the Web? It does so by publishing those standards in HTML (and, recently, in XHTML) form at its Web site, http://www.w3.org. These specifications are given three different levels:
Notes. These are specifications that usually are submitted to the W3C by a member organization, and, that the W3C is making public although not necessarily endorsing. For example, the note submitted by Microsoft to W3C on Vector Markup Language (VML) is at http://www.w3.org/TR/NOTE-VML.
Working drafts. A working draft is a specification that is under consideration and open to comment. It's inappropriate to refer to such works as standards or as anything other than working drafts. For example, the working draft for XHTML 1.1 is at http://www.w3.org/TR/xhtml11/.
Recommendations. Working drafts that the W3C has accepted become recommendations. The W3C uses the term recommendations when it publishes its standards (because the W3C is not a government body, it does not use the term standard). For example, the XML 1.0 recommendation is at http://www.w3.org/TR/REC-xml.
Besides these official specification levels, W3C also has candidate recommendations, which are working drafts that have been proposed but not yet accepted as recommendations, and companion recommendations, which augment recommendations. In fact, there are plenty of companion recommendations for XML (such as schemas, XLinks, Xpointers, and so on), and you'll find a good list of them at http://www.w3c.org/xml.
The recommendation for XML 1.0, which defines XML, is at http://www.w3.org/TR/REC-xml; you'll also find it in Appendix A, "The XML 1.0 Specification." This specification is the most important one as far as this book is concerned. Together with the associated standards (Unicode and ISO/IEC 10646 for characters, Internet RFC 1766 for language identification tags, ISO 639 for language name codes, and ISO 3166 for country name codes), this recommendation gives you all you need to understand XML Version 1.0 and create XML documents. Now it's time to put this recommendation to work, creating well-formed XML documents.