Book excerpt: Flutter is Google's UI toolkit for creating beautiful and native applications for mobile, desktop and web from a single Dart codebase. In this book we cover in detail the Dart programming language (version 2.10, with null safety support) and the Flutter framework (version 1.20). While reading the chapters, you'll find a lot of good practices, tips and performance advices to build high quality products. The book is divided in 3 parts. PART 1: It's about the Dart programming language (classes, exceptions, inheritance, null safety, streams, SOLID principles...). PART 2. It's about the Flutter framework (localization, routing, state management with Bloc and Provider, testing, performances with DevTools, animations...). PART 3. It's a long collection of examples (using Firestore, monetizing apps, using gestures, networking, publishing packages at pub.dev, race recognition with ML kits, playing audio and video...). The official website of the book contains the complete source code of the examples and a "Quiz Game" to test your Dart and Flutter skills!