Excellent Drupal 7 introduction for experienced developers
Recently, I started working with one of the best Titanium Titans on one of my mobile projects. For those people who aren't familiar with the concept, Titans in the world of Appcelerator's Titanium are the thought leaders of the project and, obviously, wicked smart developers. In one of our conversations, he mentioned that a lot of his clients need Drupal expertise and want to use Titanium with Drupal 7, and he asked me about a good introductory book for himself.
My first suggestion was Pro Drupal 7 Development, but after reconsideration, I wasn't sure if that was the best book to get him familiar with the rich feature set of Drupal. Although it explains the building blocks of Drupal itself very well, it doesn't provide guidance on the tools, tips & tricks and, most importantly, most used Drupal 7 modules.
For a developer with a pre-existing intermediate to high level of programming expertise who wants to start getting a solid feeling for Drupal 7, I'd recommend Drupal 7 Development by Example instead. I particularly found the discussion of both Drupal basics and 'must-have' modules interesting, which of course features the creation of custom content types and a quick introduction to module development, as well as usage examples for modules such as the Media module, Colorbox, Webform, Views, Views Slideshow. Since the book covers a lot of ground, you shouldn't expect the author to go into too much depth in each area, but anyone looking for a great introduction to the power of Drupal and it's powerful world of modules, this book is an excellent choice.