A: 

It looks like you can do this by getting the UINavigationItem for the current screen. You can get it from the topItem property of the UINavigationBar.

Once you have the UINavigationItem that represents your current title are you should be able to experiment with the backBarButtonItem property, then call setHidesBackButton:animated: to show the back button.

CynicismRising
A: 

Sure, you can do this pretty easily. Just set the leftBarButtonItem of your self.navigationItem to be a back button.

Dan Lorenc
there is no way to create or set a "back" button. You can only create and set square buttons.
erotsppa