Perl 6 Books and Media: Revision 3
Perl 6 Books
Perl 5 Books with Perl 6 Relevance
"Perl Best Practices" by Damian Conway. Even though this currently applies to Perl 5, most of the principles also apply to Perl 6. This book is a semi-officially recommended guideline for people developing core Perl 6 modules and tests.
Perl 6 Media