Pro Swift is powerful book for who wanna learn deeper things of Swift. It contains many concepts like functional programming, error handling, lesser known types, etc. Also book has a chapter about patterns in iOS development like MVC, MVVM, POP and OOP. Especially I liked that chapter, because It is focusing philosophy behind of them instead of how can apply.
I have already knew many topics in this book however I've also learnt new things like contigiousArray, command-line Swift and I've remembered the topics that I've learnt before the book. If you don't specially focus Swift's advance topics yet, Pro Swift can be worth to read.