I've almost finished Learning Perl with about 10 pages left, honestly it makes me itch to find a copy of the Alpaca book just to find out more lol.
It's rare that I read about any given language beyond it's documentation or tutorials but I've rather enjoyed this O'Riley, it's understandable why the company has a good reputation (y). I even noticed a module in the appendix that might be handy for implementing a program I've always wanted but have never found one before.
Perl is a very fun language to put to work, I don't think I'd want to do any thing lengthy in Perl (~1000s of lines) but for getting stuff done it's quite handy. It also comes with a ****load of documentation hehe, not to mention I like the POD (Plain Old Documentation) style for doing things.