Writing a book on Core Data would be a challenging task. I like that fact that the book contains a reasonably complex sample application, that contains many features one would probably use in their own applications.
I do however find the book structure a bit jarring, in particular when you have read an appendix first, which too quickly covers a complex sample application. I would prefer a much softer start.
1) Start with a really simple core data sample in the early chapters. 2) After the early chapters, build the complex sample application with a Core Data flavour.
Even though this book’s focus is Core Data, I wouldn’t criticise the book for providing a refresher on topics common to most applications (e.g. story boards, application bundles, iOS user interface design etc).
I would like to see clarification of what sample code to use. One way to address this would be to put the sample code in chapter folders. The sample code is a little buggy. Although it’s been interesting finding and resolving the issues, it does distract a little from text.
Despite the issues that I have raised, I have learnt quite a lot from the text, and do not regret at all purchasing the ebook. I think that these suggestions would change a good book to a great book.