|Author||Tom Christiansen, brian d foy, Larry Wall, Jon Orwant|
|Media type||Print, Ebook|
|ISBN||978-0-596-00492-7 (print), 978-1-4493-9890-3 (ebook)|
Programming Perl, best known as the Camel Book among programmers, is a book about writing programs using the Perl programming language, revised as several editions (1991-2012) to reflect major language changes since Perl version 4. Editions have been co-written by the creator of Perl, Larry Wall, along with Randal L. Schwartz, then Tom Christiansen and then Jon Orwant. Published by O'Reilly Media, the book is considered the canonical reference work for Perl programmers. With over a thousand pages, the various editions contain complete descriptions of each Perl language version and its interpreter. Examples range from trivial code snippets to the highly complex expressions for which Perl is widely known. The camel book editions are also noted for being written in an approachable and humorous style.
The first edition, which gained the nickname "the pink camel" due to its pink spine, was originally published in January 1991 and covered version 4 of the Perl language. It was the work of Larry Wall and Randal L. Schwartz. By the time the second edition of the book was published, in August 1996, Perl had changed significantly: it now included references, objects, packages and other modern programming constructs. In response to these changes, the two original authors, joined by Tom Christiansen, rewrote the book from scratch. In July 2000, the third edition of Programming Perl was published. This version was again rewritten, this time by Wall, Christiansen and Jon Orwant, and covered the Perl 5.6 language. The fourth edition constitutes a major update and rewrite of the book for Perl version 5.14, and improves the coverage of Unicode usage in Perl. The fourth edition has been published in February 2012. This edition is written by Tom Christiansen, brian d foy, Larry Wall and Jon Orwant.
Programming Perl has also been made available electronically by O'Reilly, both through its inclusion in various editions of The Perl CD Bookshelf and through the "Safari" service (a subscription-based website containing technical ebooks). The publisher offers online a free sample of Chapter Eighteen of the third edition  and the Chapter One of the fourth edition  as well as the complete set of code examples in the book (third edition) . O'Reilly maintains a trademark on the use of a Camel in association with Perl, but allows noncommercial use.
- First edition (1991; 482 pages; covers Perl 4; ISBN 978-0-937175-64-4)
- Second edition (1996; 670 pages; covers Perl 5.003; ISBN 978-1-56592-149-8)
- Third edition (2000; 1104 pages; covers Perl 5.6; ISBN 978-0-596-00027-1)
- Fourth edition (2012; 1184 pages; covers Perl 5.14; ISBN 978-0-596-00492-7)