- Sophie is a 14-year-old Norwegian girl who is the protagonist of the novel and is very curious about philosophy. - She receives strange letters from an unknown sender while returning from school that discuss philosophy, with symbols like letters representing thoughts and a rabbit representing human beings. - The letters suggest the most important thing in life is philosophizing and attempting to understand ourselves, though there are not many questions but many answers to each. - Sophie does not tell anyone about the letters and receives more that stress the importance of wondering and not losing her sense of curiosity, though discussing it with her mother only leads to questions if Sophie is doing drugs.