I owe a debt to a reader I'll call Sabreur for submitting an extensive list of errata for Step into Xcode.  
 
I haven't reviewed all of them, but thought it important to get the list out now. The page loses most of the rich-text attributes the author supplied, making some of the notes a bit less clear; I regret that, and will try to make that up as soon as convenient. 
 
I'll log big errors separately.