This book is a waste of a good title, and I wish it would either go out of print, or be completely rewritten. It isn't so bad in and of itself, but it's useless to anyone nowadays, as the really interesting material that it tries to cover is much better addressed in Conway's excellent /Object-Oriented Perl/. (To be fair, chapter 20 of /Advanced Perl Programming/ is a very good discussion of the internals of the Perl interpreter-compiler. However, that's of real interest to very very few people.) Instead of spending their time and money on this book, learners are better off reading the other, more recent good books on Perl, flipping thru modules in CPAN, and subscribing to The Perl Journal.