Well you know my opinion.

I like using books as well. I have a lot of animals wandering around my house. When I need to learn I prefer something I can read offline.

But if your ultimate authority is anything other than that which you have locally installed then it will be somewhat wrong and you will never know when. For instance if you want to learn how to use tie effectively, the documentation in this site will lie to you about the limitations of what you have installed. This site's documentation does not include the wonderful qr// operator. You might or might not have the our keyword locally available. No book will tell you whether you do - but your locally installed documentation does. And, of course, the odds are very good that the exact list of diagnostic messages that you might get are available nowhere else than with what is locally installed.

Aw heck, I don't have time to rant properly. Besides which I already did: RE (5): Should I use $ and $# ?.

BTW for what it is worth I have been using Perl for about 2.5 years and programming for not much more than that. Of course I have a strong technical background, I have done my level best to learn, and I have had the incredible fortune to work very closely with someone whose first real job was kernel hacker in a tiger team at DEC under "Maddog" during the height of the VMS-Unix wars. You can decide for yourself how well I have learned Perl.