who vs. whom (idea)

Forget indirect pronouns and other things you never learned about in 3rd Form Grammar. The simple rule is this: When you would answer him (ends with an "m"), use whom. When you would answer he (doesn't end with an "m"), use who.

How simple is that?

Examples:

• _________ am I going to see tonight?
  I am going to see him, therefore you need a whom.

• _________ cares how pretty your girlfriend is?
  He does, so you need a who.

• ________ to send presents to, and when.
  I'll send him a present. So it should be a whom.

• ________ is this book about?
  The book is about him. It's whom again.