I'm at a CiviCRM developer training and have to share my discoveries. Before yesterday, I always felt like a CiviCRM hacker, without really knowing why, and now I think I do. For me, the difference is between knowing a few tricks to accomplish what I want to do, compared with actually understanding the code as a whole and feeling like I could responsibly contribute stuff and not just cross my fingers that I'm not missing something important. So, no, it's not a secret handshake, but here's what I've learned: 1. Dispatcher and permissions In Drupal, we have a bunch of code called the "menu system" which takes care of (among other things, like the actual visible menu), how a particular url maps onto a specific piece of code to be executed - i.e. which callback function gets invoked. This mapping of urls to callbacks is implemented by modules in the hook_menu function and stored in a table that gets rebuilt when modules get added and rebuilt or the menu c...