I very much appreciate everyone's feedback in this thread, but I'm replying here as this post (after reading through the docs of Tk) showed me that I wasn't really trying to understand callbacks, but as a few stated, Event Driven Programming.

I just didn't correlate the two so deeply, but now I fully understand the purpose of a callback in non-event driven apps (grep was a *great* example for me to grasp).

Although I don't have any need to do GUI programming, I am going to play around with it for a while so I can grasp this event-driven thing, as I want to fully understand how it works so perhaps one day I can incorporate some of their benefits into apps I do write on a daily basis.

Again, thanks to all the Monks who replied with such in-depth and thought-out posts to help me understand not just about callbacks, but programming at another level.

Thanks and regards,

-stevieb