By necessity this type of book covers a lot of ground, but it doesn't do it well. I did find a few things here that were interesting, but on the whole this isn't worthwhile.
The individual topics are explained in the context of contrived mini-apps, complete with all the UI code: the ratio of interesting (topic related) discussion to the useless wrapper is maybe 1:9.
It feels like the initial draft of the book got rejected with "use more examples & context" and author struggled to make those sensible. The result is hard to read and greatly limits usefulness.
Swift 2 Cookbook