Friend Assemblies
The C# access modifier internal defines access is only allowed within the assembly. This is what .NET 1.0 defined. With .NET 2.0 friend assemblies are allowed to access these members, too. Friend assemblies are defined with the attribute class InternalsVisibleToAttribute:
[assembly:InternalsVisibleTo ("AssemblyB, PublicKeyToken=32ab4ba45e0a69a1")]
Christian