chromatic's book, Modern Perl, has my highest recommendation:

http://modernperlbooks.com/books/modern_perl_2016/index.html

I've mentioned it before, but reading this book and applying its concepts (along with judicial use Damian Conway's Perl Best Practices) changed my view of Perl from "well, I guess I'll use it since it's here," to "I really enjoy using Perl".

Mark Jason Dominus's Higher-Order Perl was another enjoyable read, for its advice on using Perl as a more functional programming language.