What do you feel are five key areas of human resource management that all managers (non-HR managers) should have knowledge of so that they can do their jobs more effectively?

What do you feel are five key areas of human resource management that all managers (non-HR managers) should have knowledge of so that they can do their jobs more effectively?

Explain what specifically they would need to know within each of these areas and how it would/could impact their job success or lack thereof.