I'm thinking about picking up this book, but I have one reservation: Perl 6. For those that know, how much of this book's content will be relevant once Perl 6 comes out? I'd be disappointed if I bought the book and 3 months from now it's made obsolete by the next generation. Yes, I'm being an optimist as to when Perl 6 is coming out, but all the same, if I'm going to shift my way of thinking about things, I'd like for it to be relevant for more than a year...