Pro Drupal 7 Development (Expert's Voice in Open Source)
Pro Drupal Development represents the definitive guide for Drupal developers.   Many have called Pro Drupal Development the one "must have" book if you're thinking about using Drupal.  In this edition I focus on Drupal 7 and the significant changes to the APIs and capabilities presented by Drupal core.   I cover everything from building new modules, creating complex forms, interacting with the database, using the new Field API (the part of CCK that was moved into core), working with nodes, working with users, leveraging JQuery, themeing, creating web services, testing, and several other key topics.   If you're looking for one book that will help you succeed as a Drupal 7 developer, this is the book to have on your desk.