If the rest of this book is about how to use mod_perl properly, this
section is about what to do when things go wrong. It contains three
chapters:
Chapter 21 explains what various errors from
Apache, Perl, or mod_perl might indicate, and what you can do about
them.
Chapter 22 is about what you can do to fix
mod_perl problems at all stages, from configuration to compilation to
runtime to shutdown.
Chapter 23 points you to various books, online
documentation, mailing lists, etc. that can help bail you out when
you're really stuck.