by Steven J. Owens (unless otherwise attributed)
... oh, and some suggested reading material, all from O'Reilly:
I have listed them roughly in my suggested reading order, although there are a lot of caveats.
CGI Programming is done in Perl and makes some allowances that you might not know Perl, but I highly recommend that you get either Learning Perl or Programming Perl at the same time. Or both.
Learning Perl takes a more lesson-by-lesson approach to the topic, but is not geared towards learning Perl for CGI stuff. (Note: It's also been reported to have a lot of errors; check the O'Reilly site for errata and see if there's a more recent printing).
Note: The above refers to the early-90s edition of Learning Perl. The newer (blue) edition is updated and also has a section on CGI programming in Perl.
Programming Perl is more reference-oriented and generally strongly suggested by anybody with a lot of programming experience. It's the "bible" of the Perl language. Co-authored by the creator of Perl himself!
Advanced Perl Programming is pretty good. Don't let the title prevent you from cracking it open before you finish Programming Perl, however. The first five chapters explain a lot of things about data structures, references, subroutines, closures, and using eval that Programming Perl seems to take for granted. I think I'd have had a lot easier of a time with Perl if I'd had those five chapters around when I started really doing interesting stuff with data.
The Perl Cookbook is one of the most recent additions to O'Reilly's Perl books. It's just what the title says; a THICK (about 750 pages) volume of problem/solution examples, along with sample code and discussions of the issues involved. Look for me on page XXXII, near the bottom :-).
Mastering Regular Expressions is highly recommended by just about everybody involved with the other Perl books on this list. I haven't read it myself, but then again I've been using regular expressions in Emacs since forever, so I'm less intimidated by them. I still plan to get a copy of this book someday soon, so I can really understand and use regular expressions. One of my friends, also one of the guys who helped me over some rough spots early in my Perl adventure, told me "In Perl, If you can do it with a regular expression, that's probably the right way."
I skimmed through Web Client Programming in Perl and I was fairly impressed; it's a slim book but looks well worth having. This is for doing things where you want to make automated programs that interact with web servers. Perl has some powerful libraries for making doing things over the net as easy and flexible as doing things with local files. For some complex tasks, this could be really handy to have around.
I haven't looked at, nor have I heard opinions from anyone, the Perl Resource Kit, the Perl reference, Perl in a Nutshell. I'd like to hear from anybody who has things to say about them.
Also been recommended to read (but I haven't yet):
In the preface to The Perl Cookbook, the authors suggest Perl: The Programmer's Companion is good for experienced programmers who're getting into Perl, while Effective Perl Programming is about the object module, developing modules, debugging, and CPAN.
Addendum: had time to read most of Effective Perl Programming. There's a lot of stuff about idomatic Perl. Since a lot of the time this works out to be the same as "obfuscated Perl" I didn't find the material as directly useful as I'd like, but I still think it's good reading for moderate-to-advanced Perl programmers. It's always a good idea to have a solid grasp of the nuances of the language, even if you don't plan to use them :-).