Rating: 

Technically speaking this bookshelf includes all you need to learn and develope in Perl 5.x. Perl 5.10 is not covered by this bookshelf as it was printed back in 2002, but it is still valuable and usable under Perl 5.10 as far as Perl 5.10 lets you program the same way as you did with Perl 5.8 or 5.6.

Of course version 4 is there but IMHO it is less usefull, some books are missing on it and others are not available as HTML so you cannot use the global search facility of the bookshelf. This global search facility lets you look in any book of the bookshelf anytime and is one of the good things of this version.