Apologies if this was already noted...

Initial "try out" of ScreenRotations doesn't work. You can rotate the iPhone, but the button doesn't reposition.

Looked at the downloaded project and found two significant differences between the download and pages 187-189.

ScreenRotationsViewController.h needs:

-(IBAction) btnClicked:(id) sender;

And ScreenRotationsViewController.m needs method shouldAutorotateToInterfaceOrientation to comment out the fancy return and simply "return YES".

Then it works.