Updated for iOS 17. SwiftUI is radically different from UIKit. In this short book, we will help you build a mental model of how SwiftUI works. We explain the most important concepts in detail and help you build a solid foundation for understanding SwiftUI. Since SwiftUI is a large framework, the book focuses on the concepts behind the framework that we believe are essential to understand. It is not a reference for SwiftUI’s platform-specific APIs, but rather a guide to honing your intuition about how SwiftUI works. Thinking in SwiftUI is geared toward developers who have both prior experience with Apple’s platforms and a good understanding of the Swift language. When SwiftUI came out, it was a radical departure from UIKit. We wrote the first edition of this book to help you build a mental model of the way SwiftUI works. A few years have passed since then, and we’ve had the opportunity to teach this material to many teams of developers, large and small. During this process, we continued to improve and refine our approach of explaining SwiftUI’s fundamentals based on the feedback from the workshops. This new edition of Thinking in SwiftUI is the result of that journey: we rewrote the entire book from the ground up to be on par with the way we teach SwiftUI in our workshops.