Windows Presentation Foundation (WPF)
WPF provides a unified framework for building applications with rich user interfaces and interactivity. It is built on top of the .Net Framework and makes use of the managed and unmanaged code. WPF programming model allows the developers to write code once and deploy it as a standalone installed application or in a browser.

Microsoft Silverlight
Microsoft Silverlight is a cross-browser, cross-platform, and cross-device plug-in for delivering the next generation of .NET based media experiences and rich interactive applications for the Web. Silverlight offers a flexible programming model that supports AJAX, VB, and C # and integrates with existing Web applications.

Extensible Application Markup Language (XAML)
XAML is a markup language for declarative application programming. It is a tools-supported, XML-based user interface design language that maps XML markup tags to objects in the .NET Framework, enabling designers and developers to collaborate on delivering superior user experiences. Windows Presentation Foundation (WPF) and Silverlight application user interfaces are created in XAML.

Development Environments
Visual Studio and Expression Studio are tools used by the developers and UI designers. Expression Studio is primarily used by the UI designers to create the layouts, styles, animations, etc. Visual Studio is used by the developers to write the code behind to take care of the functionality and processing. Both Visual Studio and Expression Studio make use of the same project definition structure. Hence a project created in Visual Studio can be opened in Expression Studio and vice versa.

XBAP (stands for XAML Browser Application)
XBAP is a WPF application run in the browser. XBAP runs sand-boxed in Internet Explorer and has restrictions when compared to a WPF desktop application.

Download pdf WPF and Silverlight Building Rich Interactive Applications with XAML