This is the fourth in a series of videos which introduce object oriented programming (OOP) using Visual Basic.NET (VB.NET). This video demonstrates how to write methods within a class, otherwise known as behaviours or operations. It also explains that a method can be implemented either as a public procedure or a public function that returns a value to its caller. Specifically, it shows how to implement a method that saves property values in a text file and returns a Boolean True to indicate success. Finally, this video defines the term 'encapsulation' which means data or complexity hiding. Later videos in the series will cover constructors, method overloading, inheritance and method overriding.