Effective Perl Programming, by Joseph Hall and RandalSchwartz, AddisonWesley, 1998
ISBN 0-20141-975-0 Sixty short lessons in aspects of PerlLanguage, drawn from the authors' teaching and consulting experiences, designed to add to the reader's understanding and bag of tricks. Performance characteristics of RegularExpressions, symbol tables and scoping, hints for debugging, brevity vs. readability trade-offs, etc. Clean, well considered examples. A practical adjunct to the standard OreillyAndAssociates Perl texts.
This is a great bedside book. I've been reading a section a night, and my mediocre Perl skills increased noticeably after a week. -- DaveSmith
The author has much of the book online - check out http://www.effectiveperl.com/toc.html (BrokenLink? 2006-02-25) - but it certainly is worth buying the wood pulp. Makes for a quite orderly progression to the Advanced book. -- PeterMerel
Joseph Hall's blog: http://effectiveperl.blogspot.com/. Chapters 1, 2, 3, 4, and 7 of the book are available online there.