ASP.NET automatically links assemblies to a resource when compiling each code module. An AssemblyInfo object references an assembly. An assembly is a collection of types and resources that are built to work together and form a logical unit of functionality. An assembly provides the common language runtime with the information it needs to identify type implementations. To the runtime, a type does not exist outside the context of an assembly.
Commonly linked assemblies are listed in the assemblies node of the compilation section of the configuration. Additionally, assemblies can be manually added to a code resource when additional functionality for an application is needed.