This is a decent introduction to iOS programming. It is intended to be a "hands on" book, leading the reader through examples and concepts. It tries to introduce concepts as needed and not burden the reader with more than is needed at any point in time.
It's a decent intro though probably not worthwhile for intermediate to advanced programmers. Experienced programmers looking for knowledge on Objective C or iOS might find it useful (as I did) but there may be too much of the book that you end up skimming to get to the parts you care about.