- Effective Perl Programming (teaches idiomatic Perl)
- Advanced Perl Programming (just like it sounds)
- Object-Oriented Perl (discusses many cool advanced topics, not just OO)
- Mastering Algorithms with Perl (any MP3 code will likely make use of concepts in this book)
Now, that said, I'm not sure there's much that any book can
do to help you understand difficult Perl. My advice for how
to learn to read difficult Perl: write difficult Perl. Make
every line of your code count. Learn something in each
construct you fashion. There's always some way to write it
shorter, so go find it.
Of course, this will largely result in the opposite of
easily readable, maintainable code. But, you'll be surprised
at how much of that "difficult" code becomes just "normal"
after a short time of writing "power Perl." Constructs you
used to consider obtuse will soon be just common.
Brainbench 'Most Valuable Professional' for Perl