.NET Framework is a complete environment that allows developers to develop, run, and deploy the following applications:
• Console applications
• Windows Forms applications
• Windows Presentation Foundation (WPF) applications
• Web applications (ASP.NET applications)
• Web services
• Windows services
• Service-oriented applications using Windows Communication Foundation (WCF)
• Workflow-enabled applications using Windows Workflow Foundation (WF)

.NET Framework also enables a developer to create sharable components to be used in distributed computing architecture. NET Framework supports the object-oriented programming model for multiple languages, such as Visual Basic, Visual C#, and Visual C++. .NET Framework supports multiple programming languages in a manner that allows language interoperability. This implies that each language can use the code written in some other language.

.NET Framework provides enormous advantages to software developers in comparison to the advantages provided by other platforms. Microsoft has united various modern as well as existing technologies of software development in .NET Framework. These technologies are used by developers to develop highly efficient applications for modern as well as future business needs. The following are the key components of .NET Framework:
• .NET Framework Class Library
• Common Language Runtime
• Dynamic Language Runtimes (DLR)
• Application Domains
• Runtime Host
• Common Type System
• Metadata and Self-Describing Components
• Cross-Language Interoperability
• .NET Framework Security
• Profiling
• Side-by-Side Execution

The following are the new features of .NET Framework 4.0:
• Improved Application Compatibility and Deployment Support
• Dynamic Language Runtime
• Managed Extensibility Framework
• Parallel Programming framework
• Improved Security Model
• Networking Improvements
• Improved Core ASP.NET Services
• Improvements in WPF 4
• Improved Entity Framework (EF)
• Integration between WCF and WF

Intermediate Language is also known as MSIL (Microsoft Intermediate Language) or CIL (Common Intermediate Language). All .NET source code is compiled to IL. IL is then converted to machine code at the point where the software is installed, or at run-time by a Just-In-Time (JIT) compiler.

Assembly metadata is stored in Manifest. Manifest contains all the metadata needed to do the following things
• Version of assembly.
• Security identity.
• Scope of the assembly.
• Resolve references to resources and classes.

The assembly manifest can be stored in a PE file either (an .exe or) .dll with Microsoft
intermediate language (MSIL code with Microsoft intermediate language (MSIL) code or in a
stand-alone PE file, that contains only assembly manifest information.