What is Object-Oriented methodology for?

To deal with complexity

• To save you time in medium-to-large programming efforts
• To facilitate writing of more robust code
• To simplify later alterations in functionality

How can it do that?

• Better control of responsibility for changing data.
• Rich semantics make it easier to write code that reads like what it does
• Rather that code that says "do this, now do that", code talks about real-world things and their relationships.