It's not clear where you start out, but Learning Perl is a good book to start out with. It will help you up and go with useful basics. Thereafter you should probably get yourself a copy of Intermediate Perl, which explains modules and such. By the time you get through that you might have more spesific things you want to know, and "the Camel-book", Programming Perl, should end up on your desktop soon.
in reply to what does 1; does?
Testing Perl and also Perl Best Practices are very good, and you might use them both to thumb through on the buss (or similar situations) to pick up new stuff and get inspiration.
Related and very useful is also Mastering Regular Expressions.
Take a look on the shelves of the people you work with, and ask them what they suggest you start with.