This book claims to be of 'intermediate level', to fill a gap perceived by the author.
As such, it is not a good introduction to Perl for non-programmers (though it might say it is), but with
experience in a C-like language (C, C++, Java, C#...), the book really shines.
While it is more of a tutorial than a reference work, it gets to the point quickly (I think this is its greatest
strength) with good examples.
It has wide coverage, and is a good starting point in areas such as CGI/SQL/OO/Tk programming.
If the density of 'Programming Perl' intimidates, or you just want to pick up enough Perl for a specific task,
this should do nicely.
One downside is the index is quite sparse, and the book is currently in its' first printing, so if it's like
any other computing book probably has its share of errors and typos, though I've only found one so far ;-)
Also, the 'modern' in the title is marketing speak, meaning only that the book uses features not found prior to
Perl 5. 'Un-Ancient Perl Programming' might be just as good.