This is the second Preview Edition of a book about writing applications for Xamarin.Forms, the exciting new mobile development platform for iOS, Android, and Windows Phone unveiled by Xamarin in May 2014. Xamarin.Forms lets you write shared user-interface code in C# and XAML (the Extensible Application Markup Language) that maps to native controls on these three platforms. This book is a Preview Edition because it’s not complete. It has only 16 chapters and doesn’t cover some important topics. The final edition of the book wil l probably be published in the summer of 2015. l probably be published in the summer of 2015.