My very first exposure to Perl has been through an old copy (Perl4, I think - in Perl5 days) of the Llama book. For the rest I've not read any book but for sample chapters found online, and most of my education was carried out with the help of clpmisc (which eventually I had to leave as it became too huge a time sink) and the docs, with a mutual exchange, for I was often referred to the latter, and when I found something I couldn't understand in them, I asked for clarification; and it is now continuing here - because there's always something new to learn and I'm not only talking about very advanced stuff, but also about basic stuff that that has been inadvertently sidestepped for a surprisingly long time.

Taking all of this into account, two books that I'd like to read are:

• Damian Conway's Object Oriented Perl,
• Mark Jason Dominus's Higher-Order Perl

The former, both because it is harder for me to grasp OO programming concepts in general, and OO Perl programming in particular, than other generic concepts and techniques, and because the sample chapters and other stuff I read from Damian positively influenced my judgement. Or biased it...

As far as the latter goes: ditto as above wrt judgement bias! But most importantly, even though I've not received a formal CS training, it seems I have a natural penchant for FP techniques and concepts, probably as a consequence of my mathematical interests. (I'm studying Physics, but I should have chosen Mathematics instead!)