Attributes and behaviors are encapsulated to create objects.
OO modeling is close to how we perceive the world.
Implementation details are hidden from the outside world. We all know how to use a phone, few of us care how it works.
The packaging of operations and attributes representing state into an object type so that state is accessible or modifiable only through the objects' interface
Encapsulation lets builders of objects reuse already-existing objects, and if those objects have already been well-tested, much larger and more complex systems can be created.
