IMHO, Python is also huge nowadays. :( (The language itself, that is, not counting the 500K+ third-party libraries that it has nowadays.)
As for the Camel book, what I liked about it is that it explains why Perl is the way it is... the underlying philosophy. Once you know that, it starts making a lot more sense. You usually didn't get that with books like "Learn Perl in 21 days" or something.