[Exim] [slightly OT] decent Sendmail book?

Apologies for the non-exim content, but the reason I switched
to Exim was the absolute incompressibleness of sendmail mgmt.
Now I would never go back (love it ;>).

I continue to use Exim in situations I control, but as a sysadmin
who is increasingly pulled into edge device support (from my
expertise on the server & data center side), a knowledge of
sendmail configuration has become a requirement. I own the current
version of Allman's Sendmail ref (*the* incompressible book of all
time), but what I need is a book that covers clearly, understandably,
sendmail conguration.

Is there any such book? I'm sure there are plenty of you out there
in similar situations forced to support 100lb gorilla products.

Thanks, and apologies again,

- michael