Extension methods allow us to add functionality to systems we don't control. They also allow us to write code that is easier to read. In this video, we are going to go over what extension methods are, how to write them, and when to use them. Source Code: Mailing List: Purchase Courses: 0:00 - Intro 3:16 - Creating and using extension method 8:15 - Extension method classes and namespaces 10:59 - Extending methods from third party libraries 19:48 - When to use extension methods 21:30 - Extending methods for interfaces 23:03 - When not to use extension methods 27:01 - Summary and concluding remarks Thanks Ralfs HBK