Pass data back to the previous controller

Question

I have two controllers in the storyboard, embedded in a NavigationController, and there is a segue to switch between these.

Passing data from the first controller to

Answer 1

I've been studying all of the variants to this question of how to pass data from one view controller to another and have come to see that Apple's Second iOS App Tutorial has not only the code but a lovely explanation of everything involved.