The book is intended for web application programmers, game developers, and other software engineers. Because of its dual focus (Dart and HTML5), the book can appeal to both web developers who want to learn a modern way of developing web applications, and to developers who seek guidance on how to use HTML5. The audience would include mainstream programmers coming with an object-oriented background (Java, .NET, C++, and so on) as well as web programmers using JavaScript, who seek a more structured and tooled way of developing. Both groups would leverage their existing knowledge and expertise: the first, by offering them a way of developing modern web applications using techniques they already know, and the second, by giving them a more productive and engineered way of developing (business) web applications. The article at the following link describes well what Dart has to offer for the web developers of the future:

http://news.cnet.com/8301-1023_3-57613760-93/mixbook-sees-perfect-storm-for-googles-dart-language-q-a/.