Our look is the result of reader comments, our own experimentation, and feedback from distribution channels. Distinctive covers complement our distinctive approach to technical topics, breathing personality and life into potentially dry subjects.

The animal on the cover of Learning Perl Objects, References, and Modules is an alpaca (Lama pacos). The alpaca is a member of the South American camelid family, which is closely related to the more familiar Asian and African camels. South American camelids also include the llama, the vicuna, and the guanaco. The alpaca is smaller (36 inches at the withers) than a llama, but larger than its other relations. Ninety-nine percent of the world's approximately three million alpacas are found in Peru, Bolivia, and Chile.

The evolution of the wild vicuna into the domestic alpaca began between six and seven thousand years ago. The specialized breeding of alpacas for fiber production wasn't developed until around 500 B.C. The Incas developed the alpaca into the two distinct fleece types, the Huacaya (pronounced wa-kai-ya) and the less common Suri. The main difference between the two types of alpacas is the fiber they produce. The Huacaya fleece has crimp or wave; the Suri fleece is silky and lustrous and has no crimp. Alpacas are prized for their fleece, which is as soft as cashmere and warmer, lighter, and stronger than wool. Alpaca fleece comes in more colors than that of any other fiber-producing animal (approximately 22 basic colors with many variations and blends).

The lifespan of the alpaca is about 20 years. Gestation is 11.5 months, producing one offspring, or cria, every 14 to 15 months. The alpaca is a modified ruminant, not only eating less grass than most other animals but converting it to energy very efficiently. Unlike true ruminants, they have three compartments in their stomach, not four, and can thus survive in areas unsuitable to other domesticated animals. Alpacas are gentle and don't bite or butt. Even if they did, without incisors, horns, hoofs, or claws, they would do little damage.

Mary Anne Weeks Mayo was the production editor and proofreader, and Ann Schirmer was the copyeditor for Learning Perl Objects, References, and Modules. Matt Hutchinson and Claire Cloutier provided quality control. Jamie Peppard provided production assistance. Lucie Haskins wrote the index.

Ellie Volckhausen designed the cover of this book, based on a series design by Edie Freedman. The cover image is a 19th-century engraving from Animate Creations, Volume II. Emma Colby produced the cover layout with QuarkXPress 4.1 using Adobe's ITC Garamond font.

David Futato designed the interior layout. This book was converted by Andrew Savikas to FrameMaker 5.5.6 with a format conversion tool created by Erik Ray, Jason McIntosh, Neil Walls, and Mike Sierra that uses Perl and XML technologies. The text font is Linotype Birka; the heading font is Adobe Myriad Condensed; and the code font is LucasFont's TheSans Mono Condensed. The illustrations that appear in the book were produced by Robert Romano and Jessamyn Read using Macromedia FreeHand 9 and Adobe Photoshop 6. This colophon was compiled by Mary Anne Weeks Mayo.

The online edition of this book was created by the Safari production group (John Chodacki, Becki Maisch, and Madeleine Newell) using a set of Frame-to-XML conversion and cleanup tools written and maintained by Erik Ray, Benn Salter, John Chodacki, and Jeff Liggett.