Swift in Depth

Introduction

The book Swift in Depth (author Tjeerd in 't Veen, 2019, 368 pages) is not another introduction to the Swift language for beginners. It is a deep dive into advanced concepts that every serious iOS/macOS developer needs. If you have already mastered the basics of Swift and want to write cleaner, safer, and more performant code, this book will become your desktop guide.

What the book is about

The author systematically covers complex topics, starting with advanced use of protocols and generics, and ending with memory management, functional programming, and error handling. Each chapter contains numerous practical examples and explanations of why a particular approach is preferable.

Who this book is for

The book is intended for developers who already have experience with Swift (at least 1–2 years) and want to move to the next level. It will be useful for both iOS developers and those writing for macOS, watchOS, or tvOS. Beginners just starting to learn Swift will find the book difficult — it is better to start with Apple's official guide or more basic materials.

What the reader will learn

• Advanced protocols and protocol-oriented programming — how to design flexible and extensible architectures.
• Generics — from basic templates to complex constraints and associated types.
• Memory management — ARC, strong and weak references, closures, and memory leaks.
• Functional programming in Swift — map, flatMap, filter, reduce, monads, and functors.
• Error handling — creating custom error types, throws, rethrows, Result.
• Encoding and decoding — Codable, JSON, PropertyList, custom strategies.
• Asynchrony — Grand Central Dispatch, OperationQueue, async/await (in the context of Swift 5.5+).
• Testing — writing tests for complex scenarios, mocks, and stubs.

Strengths

One of the book's main advantages is the depth of explanation. The author does not just show syntax but explains why the language is designed the way it is, and what trade-offs lie behind a particular decision. The code examples are realistic and not detached from real life — you can apply them in your projects today.

The book is written in a lively, accessible language, with complex concepts broken down into small steps. The chapters on memory management and generics deserve special mention — they are among the best in any Swift book.

Who it is recommended for

Swift in Depth is a must-read for anyone who wants to become a senior iOS developer or gain a deeper understanding of Swift's internals. If you feel stuck at an intermediate level and don't know how to move forward, this book will be your springboard. It will also be useful for developers transitioning from Objective-C to Swift, helping them avoid common mistakes and write idiomatic code.

Overall, Swift in Depth is one of the best Swift books for experienced developers. It does not provide ready-made recipes but teaches you to think and design correctly. I recommend it to everyone who takes their professional growth seriously.