I bought this book so it would provide me with domain-specific pieces of usability knowledge, but it failed at that. Althought there are concrete examples, there's nothing learn from them, as the explanations are so general they almost seem canned. It just takes basic usability concepts and applies them to popular domains, without going into any depth. And you don't need another book for that. The writing style often feels like a desperate attempt to beef up the volume. This isn't a useless book for an absolute beginner, but Steve Krug's "Don't Make Think" is several times thinner, and will teach you just as much, if not more.

The authors are long-time professional Perl trainers and it clearly shows: the selection of material, organization and presentation style are honed and distilled to be worth paying for hourly. The book is well-balanced beteween theory and practice being divided into several thematical chapters each starting with a short intoduction followed by concrete receipes, accompanied with examples. It's also very usable as a reference as receipes are clearly named and easy to find.

If you got a basic hang of Perl and are starting to love it, get this book now. This is a rare one, teaching Perl beyond syntax and common module usage.