It's also become a language that is feature rich. The ins and outs of Perl programming are certainly covered in this book. There is a feeling of thoroughness and depth throughout that won't leave too many questions to ask of Perl people on the internet. The introduction is a little bit like the Beginning Perl book that Wrox previously released and the Basic Concepts section will give some useful hints that may not be all that obvious. It's at the third chapter that things begin to get heavy with the section on scalars and the fact that scalars can be divided into three groups which are numbers, strings and references.
Operators are the stuff of chapter four where more data types are introduced and demonstrated.
The basic syntax of the language is covered by structure, flow and control. This is mostly comprehensive although probably a bit brief for someone who is a Perl programmer already. The rest of the book goes into all of the parts of Perl that might interest you just now. Sections on networking Perl and Object Oriented Perl are particularly interesting. The chapter on debugging isn't the kind of thing that I've been able to get hold of easily from elsewhere.