Hands down the best coverage of Perl fundamentals available. And a fantastic guide to object oriented Perl. If you are still writing a lot of Perl apps, this is a must have.
Update: Against my better judgement, I told my wife that I had reviewed a (gasp!) computer book on goodreads. She has given me notice that my 'friend' status is now under review.
First few chapters were a good review of the perl and even after coding in perl for awhile I picked up a few useful tips. Later chapters that delved into various cpan packages became less useful to me. In the end, it's a very useful book for those who are tied to perl, but I've since moved to ruby for objected oriented designs so the book became less useful to me.
This book may be a little dated now--and good luck finding a decent price on a used copy--but learning from Damian is the way to go. I first started to get OOP in Perl reading this book. The text starts simple and gets pretty deep into object oriented programming concepts. Pick up a copy if you find one for a decent price.