By the same author of last year’s well-regarded front end drupal; This similarly-sized book is aimed more at beginners.
The Definitive Guide to Drupal 7
If last year’s professional WordPress is the must-have book for WordPress developers, then definitive is at least the equivalent for Drupal developers.
Pro Drupal 7 Development
Learn How to Use the Content Management Framework to Create Powerful Customized Websites.
Drupal’s Building Blocks
Quickly Building Web Sites With CCK, Views, and Panels
One question that is going to come up is how current is this book with the recent arrival of Drupal 7? Except for CCK, most of the content is still relevant.
Sam’s Teach Yourself Drupal in 24 Hours
If You Have 24 Hours to Spare, Why Not Learn Drupal?
Front End Drupal
Designing, Theming, Scripting
Tools and Techniques for Learning to Create Themes for the Drupal 6 CMS.
Drupal 6 Themes
Learning the Many Ways to Theme With Drupal 6