There are several themes in the novel "Anne Frank: The Diary of A Young Girl." One of the themes is the sacrifice of one human being for another. The act of hiding people at the risk of your own life and giving of your food, living space, and friendship to spare the lives of people around you.
"An underlying theme of Anne's account is man's inhumanity to man. Simply because of her religious beliefs, Anne is confined and lives in constant fear of death. Eventually, she does die, along with over six million other Jews during World War II."
Yet another theme is what happens to people when they are imprisoned. How do they change? What happens to people when they try to live, as the Franks did, for two years in a small area with little food, space, entertainment, and no freedom?