All of the code in this book has been updated for Swift 3.0, which was a major update to the Swift language. Throughout the book, you will see how to use Swift’s capabilities and features to write better iOS applications. We have come to love Swift at Big Nerd Ranch and believe you will, too.

Other additions include new chapters on debugging and accessibility and improved coverage of Core Data. We have also updated various chapters to use the technologies and APIs introduced in iOS 10.

This edition assumes that the reader is using Xcode 8.1 or later and running applications on an iOS 10 or later device.

Besides these obvious changes, we made thousands of tiny improvements that were inspired by questions from our readers and our students. Every chapter of this book is just a little better than the corresponding chapter from the fifth edition.