I love Pro Second Drupal Development
I have been programming for years, but new to PHP and Drupal. This book was (and is) exactly what I need to get things done. It’s pretty complete — I think the entire Drupal 6 API is discussed. It’s well organized. It has a good index (!!), and it has non-trivial examples that work you through to the end of the topic.
I am struggling in some cases — Drupal’s greatest strength is the number and scope of its contributed modules, and this book does not address them. However, there are some modules that are effectively part of core Drupal (or ones that will be soon). Most modules are poorly documented and have a few bugs or limitations — as a new Drupal developer, I have found it hard to know how to isolate problems — in modules, and in my own code. One module, briefly discussed (Devel) is a huge help, but very little is written about it.
While I understand that a book like this cannot cover everything, a section on practical debugging, testing, problem isolation and so on would have done wonders for me.
Still the book is a must have for me.
Pro Drupal Development Second