The release of Windows 8 represents a bold entry into the world of tablet PCs by Microsoft. With Windows Store applications it is possible to write highly responsive, touch-friendly applications that run efficiently on multiple form factors including new ARM devices. The Microsoft team has taken great care to accommodate your existing knowledge by embracing both C# and the managed code stack and XAML technologies, but there are important fundamental differences. In this deep dive of the Windows 8 stack, Jeremy Likness covers the inner workings of the engine, reveals how it relates to traditional Silverlight and WPF development, and highlights the areas that are important for developers to understand as they transition from the Silverlight and WPF platform to Windows 8 with help from the Portable Class Library (PCL.)