This video reviews the fundamental concepts of Object Oriented Programming (OOP), namely: Abstraction, which means to simplify reality and focus only on the data and processes that are relevant to the application being built; Encapsulation meaning that data and the programs that manipulate those data are bound together and their complexity is hidden. Encapsulation is often achieved by means of class libraries (dynamic link libraries, or DLLs); Inheritance which allows a class to derive its methods and properties from another class. Inheritance might be used to define an extensive hierarchy of super classes and subclasses; Polymorphism meaning different subclasses of the same superclass, which therefore share the same interface, can implement those interfaces in their own ways. Polymorphism is implemented when classes override the code of the methods they inherit. The video also reviews the relationship between objects, otherwise known as entities, and classes, which are the code used to create objects. Chapters: 00:00 What is an object? 01:02 Abstraction 01:38 Objects from a class 03:43 Encapsulation 05:28 Inheritance 07:11 Polymorphism 08:18 Summary of OOP concepts