Helen Keller's book focused on her life and her own becoming a socialist--the ideological many Nazis despised the most. Her book was vocally torn apart and physically burned with glee by the Nazis during the book burnings. She later commented with contempt on their actions.
Ernest Hemingway's book centered around anti-militarism, which would be a detrimental mindset to the Nazi party in their dreams of world domination. It also was oft called a'sex-book' for its themes of sexual liberation. His book was verbally called out by many when it was burned.
Erich Remarque's book contained a lot of mental weakness of soldiers on the battlefield, an antithesis to the Nazi regime. Bringing singularity, personality, to soldiers was nigh forbidden. His was a favorite of many to call out in their fire oaths, eager to burn the ideas inside.
