Mastering Perl is already on the shelves and in people's hands, but I'm still updating the Mastering Perl working copy based on the feedback I'm getting. Maybe there will be a second edition in a couple of years, and if so, the book will be ready with updated material and even more Perly goodness.
rjbs suggest some changes to Chapter 2, "Advanced Regular Expressions", to properly note the perfomance penalty of
$&. I used it in an example to motivate not using it, but then forgot to say why you shouldn't use it.
Andy Lester suggest that I add DBI's tainting features to Chapter 3, "Secure Programming Techniques", and so it has come to pass.
I've also made the odd errata correction.