Very useful for those experienced in sendmail configuration
but wanting a quick overview of the options, rules and
delivery agents.

It's useful if you have to go somewhere without lugging
the full book with you, as it comfortably fits in the
pocket and is very thin.

You will need the full sendmail book to get the best from
it as the descriptions are one or two lines, and it is not
suitable for beginners, but for the more experienced it
will prove invaluable.