Harry Potter and the Half-Blood Prince Theme of Friendship

Friendship is the key factor that separates both Harry and Dumbledore from Voldemort. Where Harry cultivates two great friends, Voldemort prefers isolation. Voldemort has never had a friend in his life, thus, making it easier for him to inflict the horror he does upon the world. Harry's friendship fuel his ability to love, to empathize, and, like Dumbledore, to see the best in those around him.

1. What friendships are tested in this story, and how are they tested?
2. What does it mean to be a good friend in the world of this story?
3. Who would you consider to be Dumbledore's friends? What is his relationship with Harry like?
4. Does Voldemort have any friends?