I had to throw my vote in here against Learning Perl and for the Camel Book. I learned by reading the Camel, switching from C++. As it turned out, the switch was permanent (it's been over 10 years, perl is definitely my main language now). But although I've tried going back to it, I still can't recommend Learning Perl for people who already know how to program.

When you already know what you're looking to learn in a new language, the Camel Book gives you all you need as fast as you can handle. It's an exhilirating journey at top speed.

Learning Perl feels more like a horse and cart to me.