Cocoa Programming for Mac OS X - followup

So far the neatest part of working though this book has been thinking about NIBs. The NIB stores the objects that compose the UI. It can literally store archived instances of objects which are deserialized / unarchived when the NIB is loaded. I'd like to find some time to dig into the details more - or perhaps just see if I can take a nib file apart manually. A bit like freeze-drying. And in both reality and analogy, I don't really understand in any detail how it works.