"DocBook: The Definitive Guide"
    by Norman Walsh and Leonard Muellner
    with contributions from Bob Stayton
    ISBN: 156592-580-7

This book is a gentle yet thorough introduction to the DocBook DTD (which is
used by, amongst others, the FreeBSD Documentation Project).  A dead-tree
edition of the book is published by O'Reilly & Associates, Inc., but the text
is freely licensed under the GNU FDL.

The current edition purports to document DocBook v4.4 with the EBNF,
HTML Forms, MathML and SVG modules.

Author: <nwalsh@nwalsh.com>
WWW:    http://www.docbook.org/