Drupal has a comfortable surface, but this often hides the processes that take place inside Drupal.

This presentation concetrates on the core of Drupal and examines how different key concepts of Drupal play out there.

The inside of the Drupal place is just the place to look for its logic and consistency which is often hard to grasp if you get distracted by the surface and too many modules.

Understanding this logic makes it easy to start with module development. (The presentation includes an easy beginner module, that I build according to Van Dyks instructions)