Eric Lippert did a great series on covariance and contravariance and how they are implemented in C# and various design decisions which went in to it. I would hi

Eric Lippert did a great series on covariance and contravariance and how they are implemented in C# and various design decisions which went in to it. I would highly recommend it if you use C#. http://blogs.msdn.com/b/ericlippert/archive/tags/covariance+and+contravariance/ http://blogs.msdn.com/b/ericlippert/archive/tags/covariance+...