This is the list of books I would recommend. I've ordered the list from least advanced to most. I would only recommend Learning Perl if you have no real programming experience. Otherwise, everything you really need cover is in the first few chapters of Programming Perl.
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| Learning Perl, Randal Schwartz, Tom Phoenix, brian d foy, O'Reilly 2005 |   |
| Programming Perl, Larry Wall, Tom Christiansen, Jon Orwant, O'Reilly 2000 |   |
| Mastering Regular Expressions, Jeffrey E.F. Friedl, O'Reilly 2006 |   |
| The Perl Cookbook, Tom Christiansen & Nathan Torkington, O'Reilly 2003 |   |
| Perl Hacks, chromatic with Damian Cnway and Curtis "Ovid" Poe, O'Reilly 2006 |   |
| Object Oriented Perl, Damian Conway, Manning 1999 |   |
| Perl Medic, Transforming Legacy Code, Peter J. Scott, Addison-Wesley 2004 |   |
| Perl Testing, A Developer's Notebook, Ian Langworth & chromatic, O'Reilly 2005 |
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