Eve Maler has marked the tenth anniversary of the XML spec by posting an online copy of the book she and Jeanne El Andaloussi wrote on vocabulary development: Developing SGML DTDs: From Text to Model to Markup.
There is a huge body of knowledge, craft, and/or art about document analysis, vocabulary design, and the use of markup in systems that went into the design of SGML and XML. (Some call it “the SGML methodology” as opposed to “SGML” or “the spec”.) Almost all of it circulates largly in oral tradition; Maler/El Andaloussi was for a long time the only, and is still one of the best, attempts to write it down.
Thank you for the birthday present, Eve!