In the book you will be told to access the NIB and you wont find if you are are using a fairly new set of tools. Instead you will find an XIB. For all purposes in at least the first few chapters that I have made it through so far there will be no difference. When you dig down you will find that the XIB is an xml definition file and not a compressed file containing the objects. Thats a bit simplified and you can do some research on all the differences and what each is and the benefits of moving to XIB. I whent through all that just to make sure I was editing the right file and I hope that posting this here might save some people a little bit of time. Though latter you will really want to go learn what the differences are in case you run across some documentation referencing NIB in more detail.