What is the theme in When Nietzsche Wept by Irvin D. Yalom?

Fear is a theme throughout When Nietzsche Wept. At the beginning, Dr. Josef Breuer is amazed by Lou Salome, not only because she is beautiful and very intelligent but also because she seems to not have any fear. She is unafraid of what will happen to her if she bucks all social customs. Her lack of fear draws others to her, especially those who are paralyzed by their own fears.