I suggest you start with my book recommendations. But if those don't seem to meet your needs then feel free to browse the links I provide on over 165 available Perl books.

Top 100 Free Books Free Chapters

Beginning Perl Advanced Perl

Beginning CGI Advanced CGI

Free Online Book Chapters
Several author/publishing companies allow online viewing of selected chapters from their books. From their viewpoint you get more of a chance to see how good the book is, so that you'll want to go out and buy the book. From your viewpoint it gives you a chance to ensure that the book content meets your needs. In some cases an online chapter might even provide enough technical information to completely avoid purchasing the book.

You have a choice of reading the chapters online, saving the pages using your browser's built-in page Save features, or of using one of the offline website copiers (I suggest HTTrack). In some cases the chapters are provided as PDF files, which you can download directly.

The following sites (listed by book title) provide online viewing of selected chapters from books.

• Advanced Perl Programming
  
• CGI Programming with Perl
  
• Beginning Perl for Bioinformatics
  
• mod_perl Developer's Cookbook
  
• Perl & LWP
  
• Practical mod_perl
  
• Programming Web Services with Perl
  
• Writing Apache Modules with Perl and C