From the release of version 5 onwards, it has been possible to write Perl code in an Object Oriented idiom. Sadly, the way to do this in Perl has not been well explained until now, especially if object oriented programming is new to you. Damian Conway's book does an excellent job in pointing the way. Concepts such as inheritance and polymorphismare dealt with in an easily digestible way, often with a touch of humour.
The opening chapters take you through a short guide to Object Orientation and Perl before launching you into class creation. Subsequent chapters cover inheritance, polymorphism, overloading, encapsulation, genericity, multiple dispatch and persistence. All these chapters describe clearly how these concepts are undertaken using the Perl language. For those already comfortable with OO concepts, appendix B compares OO Perl with Smalltalk, C++, Eiffel and Java. Where relevant, references are made to the Comprehensive Perl Archive Network (or CPAN).
Details are given in the book on how to access the Manning web site. From there you can get all the sources to the examples and access a forum where you can place questions to the author.
Sadly, the book is badly spoiled by a number of typographical errors. I am saddened that such a good book is so badly littered with them that I did at one point question the terminology I was being told. Although these are listed on the Manning web site (15 pages so far when printed), I believe this blights what is otherwise an excellent book.