docbook-tools is a collection of all the free software tools you need to work on and format DocBook documents. RPMs are provided for those using RedHat Linux; the sourceware are all conveniently available from a single place if you're using some other OS. For those curious about DocBook, it is an SGML (or XML) DTD for writing technical manuals that cover hardware or software. It provides a standardized set of tags for all the kinds of things you need when you're writing software documentation and such things. Sourceware - docbook-tools home is
here.
