Prism provides guidance designed to help you more easily design and build rich, flexible, and easy-to-maintain Windows Presentation Foundation (WPF) desktop applications, Silverlight Rich Internet Applications (RIAs), and Windows Phone 7 applications. Using design patterns that embody important architectural design principles, such as separation of concerns and loose coupling, Prism helps you to design and build applications using loosely coupled components that can evolve independently but that can be easily and seamlessly integrated into the overall application. These types of applications are known as composite applications.

Prism includes reference implementations, Quick Starts, reusable library code (the Prism Library), and extensive documentation. This version of Prism targets the Microsoft .NET Framework 4.0 and Silverlight 4 and includes new guidance around the Model-View-ViewModel (MVVM) pattern, navigation, and the Managed Extensibility Framework (MEF). Because Prism is built on the .NET Framework 4.0 (which includes WPF) and Silverlight 4, familiarity with these technologies is useful for evaluating and adopting Prism.