9The book introduces the programming language Dart, the language used for Flutter programming. It then explains the basics of app programming with Flutter in version 2. Using practical examples such as a games app, a chat app and a drawing app, important aspects such as the handling of media files or the connection of cloud services are explained. The programming of mobile as well as desktop applications is discussed. New important features of Dart 2.12 and Flutter 2 are described: - Null safety - Desktop Applications Targeted readers are people with some background in programming, such as students or developers.