Every book has a target audience - this book's is pretty narrow is scope - people that want to understand how theming drupal 6 works. Ric Shreves hits the target! I am a mid level drupalite - not a ninja programmer or designer but not a beginner either. I found it very helpful.

Theming is the "art" of making your website look exactly how you want it. This book shows you everything you need to know on the technical side of how to make that happen. The book doesn't give design help - there are other resources for that - but if you are a good web designer and want to understand how to make drupal "pretty" this book is the best resource out there. With this book and CSS and graphic design skills you can make it happen.

Certainly all of the information in the book can be found on http://drupal.org or on other related websites, but what I like about a book is that it is focused on just the topic at hand - "drupal 6 theming" and it is in a format designed to "cover all of the bases."

As I was reading it (I have read the whole book) I found things that had stumped me -- things that are not obvious and often left out of discussions on the drupal.org discussion forums(but if you search you can find the answer) -- like to use node-story.tpl.php you have to have node.tpl.php in your theme directory ... I saw this detail noted several times in the book.

Overall I highly recommend this book and another PACKT book Learning Drupal 6 Module Development together they are very good ways to improve your drupal skills.