What is the correct way to write
I left the book that belongs to me at home.

I left my book at home.

Explanation:

Saying "my" shows that the book belongs to me. It get the point that "I" left "my" book at home in a simple and not confusing way.

Another way you could say it is: My book was left at home.

This gives no blame to anyone. By saying "I left my book at home" you give blame to yourself. It's up to you but "I left my book at home" is more formal and common.

:)

~CaityConcerto