The book Modern Perl is freely available. “Modern Perl is suitable for programmers of every level. It’s more than a Perl tutorial—only Modern Perl focuses on Perl 5.12 and 5.14, to demonstrate the latest and most effective time-saving features. Only Modern Perl explains how and why the language works, to let you unlock the full power of Perl.“
To tell the truth, I used Perl a long time ago and I enjoyed it a lot. But later when I wanted to make bigger projects, the code bacame difficult to maintain. And when I came back to my own code two weeks later, I didn’t understand anything. Now I use Python and I don’t plan to dive in Perl again but if you use Perl, this book can be an interesting read.
Link on Amazon.