I understand that interfaces define properties and methods. A class that implements an interface provides the code for the interface, thus different classes can implement the interfaces in unique ways. My question deals with NET interfaces. To quote Balena "The .NET framework defines and consumes dozens of different interfaces, and Expert Visual basic developers should learn to use them profitably." Net has the IComparable interface. So what? I need to write the code that implements the interfaces. What's the advantage?