- Interdependency between methods and their environment
- Minimize attribute visibility
- Keep it low for maintainability
- Coupling is a "system wide" phenomenon
- Objective is NOT to have class "linked" unnecessarily
- Cohesion is a "single class" phenomenon
- Objective is to have each class "limited and focused"
- Internally cohesive, contains everything that is relevant to itself, and doesn't have things that are irrelevant.