Hello world, I just committed patch http://drupal.org/node/140218, which enables us to split module files into multiple (include) files. With this patch, it is the router's (menu system) responsibility to load the correct include file -- i.e. the include file that has the active callback's code. In other words, depending on the active callback, Drupal can conditionally load include files rather than having to load the entire world. This is an important patch as it enables us to load less code -- hence, it can offer an important performance boost. Kudos to all the people who helped make this possible. :-) The patch that has been committed implements the system to accomplish that, but doesn't actually split modules. There is only one new .inc file that has been committed with this patch that acts as an example. Now this patch landed, the natural next step would be to fire up your profilers, and to split a couple more big modules in Drupal core -- and to report back the performance improvements that you observe with that. -- Dries Buytaert :: http://www.buytaert.net/