J> I am looking for something non-Microsoft specific.
There is no DNS book, that I know of, that isn't specific to _some_ company's
DNS server software or other. _DNS on Windows 2000_ (ISBN 0596002300) is
specific to Microsoft's DNS server. And _DNS & BIND_ is, of course, specific
to ISC's BIND.
This is partly because the subjects of the DNS protocol, namespace, and
database alone aren't nearly large enough for an entire book. (Comer deals
with them in one chapter, for example.)