When it comes to learning Perl, programmers consider this book to be the undisputed bible. You not only learn every nuance of this language, you also get a unique perspective on the evolution of Perl and its future direction. The 4th edition has been thoroughly updated for version 5.14, with details on regular expressions, support for UNICODE, threads, and many other features.
Many Perl books explain typeglobs, pseudohashes, and closures, but only this one shows the motivations behind these features and why they work the way they do. It's exactly what you'd expect from its prominent authors: Larry Wall is the inventor of Perl, and Tom Christiansen was one of the first champions of the language.
In print since 1991, the book affectionately known as "the Camel" has played a central role in computing among programmers and system administrators around the world. With Programming Perl, you too will learn the most efficient ways to use this language.