README.1ST begins by explaining generalized markup and introducing SGML (and explaining why it is a good idea) and then goes through the components of a DTD, building a trivial one as an example. It then presents a walkthrough of a full DTD. Thrown in as extras are a brief chapter on HTML (viewed as an SGML application) and one on HyTime. The first was interesting, but is probably too succinct to be much use to anyone without previous experience with HTML, and the second was too brief for me to get much idea of how HyTime is supposed to work.
The most annoying thing about README.1ST is the accompanying floppy. This is supposed to have on it a piece of commercial software called SGMLab, some SGML parsing information from the SGML Users' Group, and the HTML Level 2 and DocBook DTDs. But all it has on it are two DOS .exe files, which I can do nothing at all with. (I'm running Linux, but Mac users will have the same problem.) I never expected to be able to run the SGMLab software, but I don't see why the plaintext documents couldn't have been in plaintext. After all, this is with a book which goes on at length about how one of the reasons SGML is so wonderful is that, being plain ASCII, it is completely portable!