Firstly, I have to admit that I have only skimmed the replies thus far but I truly have ready your question!

My answer to the question is... If you have read the camel book and understood it then you know the language. The camel book is IMHO the definitive description of the language. If you wish to go further or deeper, Advanced Perl Programming (the puma book?) is recommended. Furthermore, we are all in the situation of not knowing what we don't know (in detail anyways!) so if you come across something you didn't know and then come to know it, then you know you are truly making progress on the randomly meandering path to an unknown goal.