Albert Knag is Hilde's father in the book Sophie's World. He was the author of the book Sophie's World, which was written for his daughter. He had a rich imagination and created Sophie Amundsen and Alberto Knox, unaware of their "existence". Albert Knag was a born philosopher, and his novel demonstrated his wide capacity of philosophical knowledge, which he transmitted into his character Alberto Knox. However, Albert becomes too absorbed into Sophie and Alberto, as evidenced by their increasing awareness of an omniscient force controlling them. Hilde feels sympathy for the characters, and she manipulates situations to taunt Albert as if he were controlled, just like Sophie and Alberto. Albert learns from his daughter and realizes his overindulgence with his story. By the end of the novel, he travels to his daughter to reconcile.