Intermediate Perl
Learning Perl Objects, References & Modules, published in 2003 by O'Reilly (ISBN 0-596-00478-8), is a follow-up to the highly popular Learning Perl book by Randal L. Schwartz and Tom Phoenix. Just as Learning Perl features a Llama on its cover, its follow-up features an Alpaca. For this reason, they are sometimes referred to as, respectively, "the Llama book" and "the Alpaca book".
This book is written in very much the same style as its predecessor. It picks up right where Learning Perl left off, and takes the reader from the most basic features of Perl references all the way through to creating perl modules and distributing them to CPAN.
For this book, rather than using Fred and Barney as metasyntactic variables again, Schwartz used the names of characters from Gilligan's Island, a theme originally used by Joseph N. Hall in the training material he developed for Schwartz while working with Stonehenge Consulting. Those materials formed the basis for the book.
In March 2006 a second edition of this book was published under the new title Intermediate Perl (ISBN 0-596-10206-2).