Swift - a fast, modern, secure and convenient programming language - appeared quite recently and was a huge surprise for the iOS public. And now, a year later, Apple released version 2.0, followed by 2.1, which brought a number of significant innovations to the development process. This book contains comprehensive information for everyone who wants to learn how to program in Swift in order to create their own iOS applications (as well as OS X-, watchOS and tvOS applications). During the reading of the book, you will find not only theoretical information, but also a large number of practical examples and tasks, performing which you will deepen your knowledge in the material studied. Despite the fact that you have a long way to go, this will be a useful and very important experience. The book does not show how to write iOS applications, it is designed to learn the Swift programming language itself. The book will give you the opportunity to master a new language and soon start writing your own applications for the App Store or Mac App Store. Having studied the language, in the future you can independently choose for which platform to create programs - for iOS, OS X, tvOS or watchOS.