But if you don't know that common.inc is included on every single page, and
used all the time, then you clearly don't know how control flows through Drupal. Likewise, calls to databases and functions. That's very true. I spent about 5 hours reading docs, got very frustrated, and tried just jumping in. I was able to write a straight PHP theme with a variation and have a pretty good handle on that much. I also have a basic understanding of how the hooks work. But I don't know the overall flow.
The following link should help with getting a general overview: http://drupal.org/node/10858
Thank you - I'll take a look!
You can build your own understanding, however, by starting in /index.php, where all pages start, and just walking through all the calls made to generate just one page. Drupal makes very extensive use of what it calls "hooks."
That's a good idea - I'll try that. I started to look at the code but it was so convoluted I couldn't follow it. I'll try again. Must leave - have to drive 300 miles tonight....